Gardening Tips and Techniques

Weeding

What is a weed? Essentially, it’s a plant that’s growing where you don’t want it to be. Weeds are opportunistic, springing up where there’s a void in the landscape, where the soil has been disturbed, or where birds and mammals have eliminated the seeds of the fruits they’ve eaten.

Weed ruthlessly in spring and early summer, rather than waiting for weeds to grow—they’ll be easier to remove, less likely to have spread, and won’t use up the precious nutrients and water from the soil that you want your other garden plants to have. Cultivate a love of weeding—smart gardeners know it’s worth it.


Ten Weeds to Pull Now:

Bindweed (Convolvulus arvensis)#1: Bindweed
Convolvulus arvensis

Every gardener knows the horror of bindweed: the perennial, twisting, vine-like weed that climbs up the stems of other plants, defying attempts to unwind or pull its counterclockwise cling. If neglected, bindweed forms a thick mat and an extensive root system that overwhelms any garden bed—or even farm field.

Get familiar with bindweed’s arrow-shaped leaf and search for the first tendrils at ground level while weeding. If the weed is already established, pull and clip the plant repeatedly to exhaust its roots. Our plant healthcare manager recommends this trick if you’ve spotted an established vine: set up wooden stakes for it to cling to (rather than other plants); then remove the plant stake.


Buckthorn (Rhamnus cathartica)#2: Buckthorn
Rhamnus cathartica

North Shore residents know buckthorn well. It is the shrubby tree that pops up in a hedge or wooded area, then chokes out every other plant, cutting off sunlight as it spreads. As its name warns, buckthorn has thorns, adding injury to insult for those who forget to wear gloves and goggles while removing it.

Like all weeds, buckthorn is best removed when small. Dig the plant up entirely. Not sure if that sapling is a buckthorn? Identify it in fall, as its leaves stay green on the branches much longer than most other trees’ branches.


Canada thistle (Cirsium arvense)#3: Canada thistle
Cirsium arvense

Canada thistle looks like a weed, with tufty seedheads and spiny, pointed leaves that stick out like a sore thumb (wear gloves while pulling it) in your garden bed.

One reason that Canada thistle is so common: its root system spreads by runners, allowing it to produce many new plants and return year after year. To eradicate it, pull all running roots.


Crabgrass (Digitaria sanguinalis)#4: Crabgrass
Digitaria sanguinalis

Some weeds are indicators of soil health and condition; crabgrass indicates compacted soil, which is one reason you’ll find it in lawns and at the edges of sidewalks.

Unlike lawn grass, crabgrass grows in a rosette of leaves, spreading by both seeds and creeping stems. Its seedheads name it, as they resemble crab claws.

Because crabgrass is an annual, the efficient way to prevent it from spreading is to prevent it from flowering. Cut the rosette off with a knife so it won’t self-sow. (Mowing doesn’t work, as the low-growing plant is below blade height.)


Creeping Charlie (Glechoma hederacea)#5: Creeping Charlie
Glechoma hederacea

The name says it all: insidiously creeping stems allow this weed to spread like a ground cover. A perennial, creeping Charlie can thread its way through, above, below, and around other plants, making it difficult to remove.

Identify it by its scalloped leaves and those square, creeping stems. To remove: trace it back to its root nodes, then dig those up repeatedly throughout the season.


Dandelion (Taraxacum officinale)#6: Dandelion
Taraxacum officinale

It’s the poster child of weeds, yet dandelion has undeniable value, too. Its young leaves are vitamin-rich edible greens, and its bright yellow flowers are one of the earliest and best sources of nectar for emerging insects, especially bees. And who among us hasn’t delighted in picking a posy of dandelions or blowing clouds of fluffy seedheads?

But it’s the dandelion’s taproot that’s the real issue for gardeners. To remove it, wait until after a rain, then dig the taproot out completely, or that same dandelion will return next year. An old-fashioned dandelion fork is a great tool for the job.

And if you don’t quite get all the roots this year, let the survivors bloom for the bees next year before you tackle that taproot again.


Garlic mustard (Alliaria petiolata)#7: Garlic mustard
Alliaria petiolata

Garlic mustard is invasive that just one plant can spread by seed quickly, forming colonies that choke out native plants in woodlands and shady gardens.

Garlic mustard is a biennial that grows into a clumping rosette of toothy leaves in its first year, then flowers and sets seeds in its second year. The key is to pull it in its first year—a task that our ecologists and volunteers repeat each spring in the McDonald Woods. As its name declares, the plant smells strongly of garlic when crushed.


Nightshade (Solanum nigrum)#8: Nightshade
Solanum nigrum

Nightshade can be crafty in a garden bed, vining and climbing and camouflaging its wavy-edged leaves through other plants. Most gardeners don’t notice it until it has already flowered and set its distinctive clusters of mostly black berries, which are both numerous and potentially poisonous.

Nightshade grows where the ground has been disturbed; keep your garden beds healthy and uncompacted to prevent this weed. Pull or dig it out completely at the root.


Poison ivy (Solanum nigrum)#9: Poison ivy
Toxicodendron radicans

Even children learn the phrase “Leaves of three, let them be,” the apt descriptor of poison ivy.

The perennial plant can be a trickster, growing low and shrubby or high and vining. But it’s the allergic reaction that some humans have that’s the real risk—touching the shiny leaves or burning the plant can release the chemicals that cause rash and uncomfortable itching.

Always wear rubber gloves to pull or dig the plant, and dispose of immediately.


Yellow nutsedge (Cyperus esculentus)#10: Yellow nutsedge

Indicative of wet conditions, and often found in lawns, yellow nutsedge can look like regular lawn grass until it grows taller, powering up to a potential 8- to 36-inch height. Check the leaves for identification—they feel stiffer than lawn grass, and the stem is triangular (it’s a sedge, not a grass).

Pull this weed as soon as you spot it—if left unchecked, it develops underground tubers and nutlets that make it difficult to control later. Feathery, golden flowers can produce seeds too.


Weeds don't just happen at random. Different conditions favor plants that evolved in different habitats. So the particular plants that pop up where you don't want them might tell you something you didn't know about your garden.

Compacted soil: If you see mats of prostrate knotweed, spotted spurge, or plantain, take a shovel and check whether your soil is so packed down that grass roots can't penetrate and air and water can't reach them. Weeds that tolerate compacted soil often occur in lawns that see lots of traffic, such as back yards with kids, parks and playing fields or along paths. Having the lawn core-aerated frequently to open it up to air and water should help.

Low fertility: Clover tends to turn up in lawns that aren't getting enough nitrogen to support healthy grass. In fact, that might be just Mother Nature trying to provide some fertility. That's because clover is a legume that can actually collect nitrogen from the air and deliver it to the soil where other plants such as grass can use it. For that reason, clover seed used to be included in grass seed mixes and clover was considered a normal and desirable part of a lawn.

High fertility: Places that have plenty of nutrients, especially nitrogen, invite different weeds. Purslane, for example, often turns up in the rich soil of perennial beds. Other indicators that the soil has ample nutrients include lambs' quarters and chickweed. So don't assume that more fertilizer is always better for a lawn or garden.

Wet soil and drainage problems: If you have a spot where any of these plants appear often, check it out after a rain to see if the soil is saturated. Consider installing a rain garden to make the most of a low, wet spot, or at least choose plants that like their feet wet. Maybe that low place in the lawn is a good site for a river birch. Weeds that can indicate poorly draining soil, such as clay, include common chickweed and crabgrass.

Dry soil: Many weeds do better in dry soil than turf grasses or most garden plants, which is why they often sprout in droughts. But black medick and red sorrel are particular indicators.

Shade: If you've got a lot of ground ivy (a.k.a. creeping Charlie) in the lawn, it's a sign that you really don't have enough sun for grass, especially Kentucky bluegrass, to be at its best. Violets, too, congregate in shade, especially in moist soil; they are native to American woodlands and might be welcome in the shade garden. Consider replacing grass in deep shade under trees with areas of mulch or shade-tolerant ground covers or perennials.

Issues with pH: Red sorrel and prostrate knotweed thrive in acid soil, but that is not widespread in the Chicago area. We're more likely to see lambs' quarters, which prefers the high pH of alkaline soils. It's a good reminder to get a soil test that will tell you what you're really dealing with.


More Common Weed Plants

Click below to view a larger image of these plants you might find in your midwestern yard.

Wood violet (Viola papilionacea)Wood violet

White clover (Trifolium repens)White clover

Purslane (Portulaca oleracea)Purslane

Red sorrel (Rumex acetosella)Red sorrel

Spotted spurge, a.k.a. prostrate spurge
(Euphorbia maculata)Spotted spurge

Prostrate knotweed (Polygonum aviculare)Prostrate knotweed
 

 

Raised Beds

Gardeners with heavy, clay, or even tainted soil might consider constructing a raised bed outlined with durable, untreated lumber. The boxed bed is then filled with a perfect, lightweight mix of topsoil, compost, and leaf mold. Other small-space gardeners who choose containers to grow their veggies and herbs can use this same mix for their pots. Any gardener who suspects the soil is contaminated should have a soil test taken prior to growing edible plants. This is best done when the soil temperature is above 50 degrees.

Repotting Orchids

Phalaenopsis

A Phalaenopsis, or moth orchid, is called the “gateway orchid” for beginning collectors: it requires very little care, and yields great rewards with blooms that last up to three months! Early success with a moth orchid leads growers to try other species and, finally, to orchid addiction. But how do you ensure early success?

Our first video details step-by-step instructions for repotting a Phalaeanopsis orchid.

Paphiopedilum

A Paphiopedilum, or lady slipper orchid, is another popular orchid with collectors: it prefers high humidity and indirect light, faring best in eastern early morning light. But how do you ensure early success?

Our second video details step-by-step instructions for repotting a Paphiopedilum orchid, which has different watering and culture needs from a Phalaenopsis. After your initial purchase and repotting, you should repot your orchid when your plant has finished blooming.

Fall Garden Chores

Right about now, some gardeners are thinking about putting their gardens to bed and stowing the trowels and pruners. Before you do that, think about popping a few fresh plants into your containers to take your garden’s display into fall. Garden centers are awash with pumpkins, mums, pansies, decorative stems, and kale in celebration of autumn. Take a stroll through one of our 27 beautiful display gardens for inspiration and ideas. Here are some things to do now before your garden winds down.

Fall Planting

Time to Plant

September is a great time to plant some types of trees and shrubs. Cooler days, warm soils, and rain or supplemental watering help woody plants get established before going dormant. Some trees are marginally hardy in the Chicago area and should be planted in the spring. Be sure to ask an expert before planting.

Think Ahead

Think Ahead

This is the month to start planning and planting for a spring display. Daffodils, snowdrops, crocuses, tulips, grape hyacinths, and glory-of-the-snow (Chionodoxa forbesii) are just a few of the lovely spring-blooming bulbs that put on a stunning show long before most perennials and annuals begin to flower. As their name implies, snowdrops sometimes poke out of the snow-covered ground in January, a most welcome sight.

Lawncare

Lawn Care

If your turf had trouble this summer, now’s the time to address it. Cool air and warm soil are ideal for grass seed germination. Seeds have a better chance of thriving at this time of year because weeds—such as dandelions and creeping Charlie—grow less vigorously than in spring. Seeding a lawn, however, isn’t always the answer. Learn more about the many ways to care for a lawn.

Clean the Tools

Clean the Tools

We should clean our garden tools regularly—after each use is ideal—but sometimes that doesn’t happen. They definitely should be cleaned (and sharpened if needed) before you put them away for winter. Take a few minutes to do this and they’ll work better, last longer, and be easier to use. Wash or scrub tools that are used in the soil, including trowels, forks, shovels, and hoes. A wire-bristle brush is handy for hard-to-remove debris. Sharpen the edges of pruners, clippers, and shovels. To prevent rust, cover tools with a light coat of oil, and dry them with a clean towel before storing.

Drain the Hose

Drain the Hose

Freezing weather is several weeks away, but by the end of the month, start thinking about draining and storing your hoses. When water freezes inside a hose, it can cause the hose to crack. And if that happens while it’s connected to the outside faucet, it can lead to problems with water pressure in the indoor pipes. As you wind up the hose in a circle, remove any kinks that can weaken the rubber.

Take Photos and Notes

Take Photos and Notes

This is a good time to walk around your garden and take photos of all the containers, beds, borders, and foundation plantings. Make some notes about things you’d like to change or improve, or plants that you’d like to include next spring. Once the snow starts to fly, it’s fun to look back at the summer garden. It’s also a good time to take a class or two at the Joseph Regenstein, Jr. School of the Chicago Botanic Garden.

Anatomy of a Spring Planter

PHOTO: Heritage Garden troughs planted for spring.A senior horticulturist shares his colorful secrets

Smart gardeners are always on the lookout for great container plans, and this year’s trough design, masterminded by senior horticulturist Tom Soulsby, is a sunny, happy mix that would work for many a porch pot or deck display.

Why did he choose these particular plants? Soulsby was happy to share tips on plant selection and working within a container’s constraints.

Tip #1: Work with the proportions of the space.

In the low-to-the-ground containers, no plant is taller than 12 inches, and most are in the 3- to 6-inch range. Keep heights low, but allow for a range—from creeping near the ground to a foot in height.

Tip #2: Scale matters.

Flowers are intentionally small in this mix, with tulips as the largest in the bunch. Diminutive flowers—nemesia, bacopa—get their moment in the sun, and don’t disappear when they’re in the company of other smaller-scale companions.

Tip #3: Mix it up.

The riotous mix of mats, spikes, lettucey leaves, and textures is what gives the container its charm. Soulsby used 15 different kinds of dwarf, short, and smaller-sized flowers in each container, planting two or three of each to help knit the mix together.

Tip #4: Break the rules.

Yes, you could plant in clusters of threes, place the trailing plants in the corners, and put the tallest plant in the center, but the wilder, looser style of random planting suits this kind of planter better.

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Mini Daffodils
Short and shaggy, Narcissus 'Rip Van Winkle' grabs attention with its bright color and "bad hair day" charm. It's an old-fashioned variety dating to 1884. After the planter has finished its six-week course, dig out the daffodil bulbs, store them in a cool spot, then replant them in your yard this fall.

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Dwarf Tulips
Tulipa kaufmanniana 'Chopin', like many in its species, is known for its decoratively patterned foliage, as attractive before bloom as after. Tom plants just one bulb per container, since its "larger" flower dominates the mix as it blooms.

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Species Tulips
Small but mighty, Tulipa whittallii, a species tulip, makes a big statement with pointy petals and fiery, red-orange color. As with daffodils, dig up tulip bulbs post-planter and site them in your yard come fall. (If the leaves are still green, you can plant the bulbs right away after removing them from the spring containers.)

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Linaria
Also known as toadflax, linaria likes early spring's cool weather, fading fast once the weather turns warm. Linaria maroccana 'Fantasy Yellow' might get lost in a large bed, but its dwarf size and delicate-yet-heavy bloom work well in this container.

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Bacopa
Dense with tiny flowers, this sutera, also known as Bacopa Big Falls™ White (Sutera grandiflora), acts like a ground cover, trailing and spilling over container edges (it's a great choice for baskets, too).

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Sedums
Creeping plants like sedum lay low, tumbling over container edges and winding through the stalks and stems of other plants. Use Sedum rupestre 'Angelina' in mixed containers when it's small, then transplant it into garden beds, where it will keep growing in size through the season. Great bright lime color and crisp texture.

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Primrose
Popular even in Shakespearean England, primroses are perennials that can work in a container, too. Valuable for rich, bright colors, varieties like Primula vulgaris 'Primlet Golden Shade' also add lots of texture, with ruffly flowers and crinkled leaves.

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Spanish Bluebells
One of the last to bloom in the bunch, bluebells (this variety is Hyacinthoides hispanica 'Excelsior') ring in spring and provide the visual punch of taller, 10- to 12-inch flower spikes topped by dangling, deep blue bells.

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Baby Blue Eyes
A welcome spot of beautiful blue color in spring, Nemophila menziesii fills in the gaps once the earlier-blooming linaria has eased off on flower production. Lettucey foliage adds texture as the plant grows—post-container, replant it to reach its true big, billowy size.

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Bidens
In a low planter, a little trailing goes a long way. Namid Early Yellow bidens (Bidens ferulifolia) spills and trails just enough to look outstanding, not out of control.

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False Sea Thrift
The "tallest" plant here, at 12 inches high, false sea thrift (Armeria pseudarmeria) bobs above the crowd on wandlike stems, adding an airy and rather delightful touch.

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Viola
Why include simple violas? For their wonderful scent, expecially lovely in the morning. A six-cell pack of violas lets you fill in the inevitable bare spots between other plants or along edges. While this variety has an unmemorable formal name (Viola cornuta), you can look for Denim Jump Up violas at your local nursery.

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Nemesia
Dwarf size and early blooms make smaller nemesias naturals for spring planters. Tom chose Nemesia foetans 'Poetry Pink' for its particularly dense and bushy habit and riveting color combo.

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Maiden Pinks
Coral color and dark leaves work wonders in a container. Dianthus deltoides 'Shrimp' is a 6- to 8-inch variety that Tom suggests for rock gardens, too.

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Twinspur
Keep twinspur (Diascia barberae 'Juliet Light Pink') well watered, and it will reward you with plentiful blooms. When summer comes, shear it back by 50 percent, and it will start the process—and reward you—all over again.

And one final, smart, gardening tip from Tom Soulsby: regular potting soil works fine in a container like this, but do fertilize every ten days or so with a basic 10-10-10 application, to keep this wonderful mix of plants blooming beautifully.


Karen Zaworski is a garden writer and photographer who lives and gardens in Oak Park, Illinois.

Ash Tree Alternatives

Ash Tree Alternatives

Looking for a replacement for an ailing ash tree? Dr. Andrew C. Bell, curator of woody plants, offers these suggestions. The first three selections are Chicagoland Grows® introductions. Use the new GardenGuide app (available at chicagobotanic.org/app) to locate these trees within the Garden and to learn more about them.

 

PHOTO: Accolade™ Elm (Ulmus 'Morton')

Accolade™ elm
(Ulmus 'Morton')

Named by the Society of Municipal Arborists as the 2012 Urban Tree of the Year, Accolade™ elm is one of the top-performing trees for urban and residential planting in the Chicago region. This hybrid elm provides the iconic vase-shape American elm habit but is resistant to Dutch elm disease and elm leaf beetle.

PHOTO: State Street™ miyabe maple (Acer miyabe 'Morton')

State Street™ miyabe maple
(Acer miyabei  'Morton')

This maple is very hardy and free of pest and disease issues. The golden-yellow fall color, uniform habit, and tolerance to urban pollution make it an excellent candidate as a street tree. Unlike the widely planted Norway maple, miyabe maple is not invasive in our region and should be planted as a replacement for ash or Norway maple.

PHOTO: Exclamation!™ London planetree (Platanus x acerifolia 'Morton Circle')

Exclamation!™ London planetree
(Platanus x acerifolia 'Morton Circle')

Selected for its uniform, upright pyramidal habit and resistance to frost cracking and anthracnose, this planetree has excellent tolerance to urban landscape settings. The exfoliating bark that has made planetree a popular ornamental is very prominent with this selection, providing year-round interest especially in the winter months.

PHOTO: Autumn Gold ginkgo (Ginkgo 'Autumn Gold'

Autumn Gold ginkgo
(Ginkgo biloba 'Autumn Gold')

One of the finer selections of ginkgo, 'Autumn Gold' has a more upright habit that is maintained with maturity. This male selection does not produce messy, foul-smelling fruit, and its bright golden-yellow fall color has made the ginkgo one of the most beloved shade trees each autumn.

PHOTO: Fall Fiesta™ sugar maple (Acer saccharum 'Ballsta')

Fall Fiesta™ sugar maple
(Acer saccharum 'Ballsta')

Another wonderful shade tree for fall color, Fall Fiesta™ is a beautiful selection of our native sugar maple. Although sugar maples lack tolerance to the heat of crowded urban areas, they perform very well in parks and parkways. Fall Fiesta™ displays brilliant autumn shades of orange and red.

Shawnee Brave™ bald cypress (Taxodium distichum 'Mickelson')

Shawnee Brave™ bald cypress
(Taxodium distichum 'Mickelson')

The bald cypress is one of our most beautiful, versatile, and adaptable native trees. It's extremely drought tolerant once established, with finely textured, feathery foliage that turns a rusty orange-brown in the fall. Shawnee Brave™ is an upright narrow selection for those landscapes with limited space.

Winter Pruning

The Rantings & Ravings of a Pruning Freak

“When’s the best time to prune?”
“Anytime!”

It doesn’t matter what season you’re in because there’s always something that can be pruned. You just have to know the plant, its growth characteristics, its best time for pruning, and what your intentions are for that plant as it plays into the whole of your garden design.

“Well, I don’t have a design. I just plant stuff. If it lives, great. If not, then what?”

It all starts with your vision for your garden. You’ve likely seen countless photographs of gardens, viewed television programs, and taken garden tours of your own. And each time you did that, something stuck with you and you want your garden to “look like that.” Maybe it was a particular plant, a color combination, or just realizing that, “Hey! This stuff actually grows in the shade!” These elements get stored in your mind — adding up to what you would want your garden to look like or feel like.

Maybe it’s a garden that provides a shady respite from the summer heat. Or an open garden theater that celebrates the hot, sunny days of summer. It can be loose and informal, or very tightly clipped into a classic formal garden. Whatever your style, the plants need to grow within the parameters of that design, and after the initial design and build phases, pruning is the most important tool that will keep your garden spot-on with what you envisioned.

The Basic Rules of Common Sense Planting
It’s important to remember that gardening happens in four dimensions — height, width, depth, and time. Plan for what the plants will be doing over time, like growing larger, taller, and deeper. Then, don’t plant something that will grow to 60-feet tall under a power line that’s 30-feet up. Do the math. And if the tag on the plant — assuming, of course, that it’s the correct tag — says that this tree will grow to 15 feet in diameter, don’t plant it 5 feet from something — like your house or driveway. Really. Yes, it looks nice and cute sitting there fresh out of the pot, and you take a picture of your toddler standing taller than the plant. Come back in ten years when the toddler is a kid and the plant is a real tree. Avoid the disappointment and frustration at the beginning — I’m talking about the tree. You’re on your own with the kid.

One overarching word of advice for your pruning technique is not to leave stubs or flush-cut. Most branches have a visible collar of folded bark at their base where the branch grows out from the supporting structure — a trunk, limb, or branch. This collar is all that needs to remain when the cut is complete. Leaving more than that, a bit of the branch for example, is a stub. You have a stub if you can hang your hat or your jacket from it. The plant will waste energy shedding this (plant’s version of a hangnail), and as it unevenly sloughs off over time, the site becomes an entry point for rot, disease, and pests. You don’t want that. And by flush-cutting this material, you make it even more challenging for the plant to close the wound. That’s what that little collar of material is — the plant’s built-in bandage. No need for petroleum products to close the cuts — these plants were created with their own internal first-aid system. Let them do their own thing. Just give them a good start and leave them alone.

Coppicing
So now it’s winter — dormant time. This is the best season of the year to perform the most radical cuts of all, short of cutting the thing down. But then again, you may want to do just that!

PHOTO: Pruning willow

There comes a time in the life of some plants when cutting them down is exactly the right thing to do!

Coppicing is the horticultural practice of whacking down younger trees, virtually to the ground, leaving short stubs sticking out of the soil (it’s not dirt — you wash dirt off of your car or your dog or your kids). No need for them to be any longer than your finger. And be sure to use clean, sharp saws and pruners. Ragged cuts and tears only invite pests and disease by offering an easy port of entry. Life is tough enough — you don’t want that.

Primarily, coppicing is a technique used on trees to alter their growth habits from single-stem trees into multi-stemmed ornamentals, or more shrublike plants. Willows lend themselves handily to this practice, wherein a healthy, established young willow (Salix alba ‘Britzensis’) regrows over successive seasons into a more shrublike plant resembling a red twig dogwood. It works well when you want that look in an environment that’s too harsh for dogwoods, but in which willows can survive, such as winter salt spray from a road, or drying, frigid winter wind.

Rejuvenation
We can coppice shrubs, too. Take, for instance, the red twig dogwood, an old favorite. Over the years, the red becomes gray, the stems become overgrown and brittle, and trimming with shears or hedge trimmers over successive seasons creates a dense thicket of twigs on top with leggy, open stems at the bottom. It looks like an umbrella with extra handles and nothing like those pictures in the gardening magazines. There is good news — you can have a shrub that looks like it came straight out of a gardening magazine by midsummer this year! If it’s properly sited (sufficient sun, water, and drainage), and the roots are established and healthy, then this is the winter to coppice the shrub when it’s the most dormant. My general rule is to cut between Super Bowl Sunday and St. Patrick’s Day (yes, you can do this later, even after buds break — just not too long after). The healthy new stems will all grow back straight, shiny, and colorful — an exciting and welcome bright spot for next winter, which is the primary reason for planting red twig dogwoods — winter interest!

When you opt for this process of going medieval on the plant, it actually spurs the complete, new regeneration of the entire plant above ground. Yes, at first it will just sit there, apparently doing nothing, and looking like a goner. But give it time. What you don’t see is the plant figuring out that it needs to develop new shoots, which will bud right out of the stubs you left behind. Just leave them alone and water the shrub if rainfall drops below 2 inches per week. And it’s always best to give it a couple of good, deep waterings per week rather than spotty, shallow daily passes with the hose or sprinkler.

You want the water to penetrate down into the root zone. If you had x-ray vision, you’d see the dense, rounded mass of roots extending beneath and around the shrub, and each root fiber poking around in the soil looking for water, nutrients, and oxygen. The spaces within the soil allow for the passage of these elements to the roots. Seeing the water percolating through the soil and into this zone may help you to better understand how plants grow, and enable you to more successfully address the plant’s watering requirements — especially now that you’ve cut it down! Forget what the neighbors might think, because you can rest assured that by the end of summer they’ll be envious of the new; perfectly shaped red twig dogwoods in your garden.

Small-Space Gardening

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Here, Garden experts offer some suggestions for the small garden, whether an urban backyard or a rooftop, a border around a townhouse patio, or plant-filled pots on a balcony or deck.

Small outdoor spaces can be dramatic or charming or meditative. In small urban gardens, your goal may be to block a less desirable view or soften the building next door. In that case, according to Tim Johnson, the Garden's director of horticulture, choosing the right plants becomes more critical when space is limited.

"If you're planting a hedge, consider plants that are more narrow in habit. For example, Techny arborvitae (Thuja occidentalis 'Techny') is popular, but for a small area, pyramidalis arborvitae (T. occidentalis var. pyramidalis) may work better," he said. Plants that are narrow, dwarf, or slower-growing may require less pruning to keep them within the confines of the garden.

Don't overlook walls as opportunities to enhance your space. Growing vines on a fence or stair rail or creating an espalier—a fruit tree or ornamental shrub trained to grow flat against a house or a garage or a fence—also creates a sense of enclosure.

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Consider planting a small space in layers so there is something of interest at all levels.

"There are many options for adding vertical elements to give height, such as really narrow columnar trees as well as using the horizontal ground plane," says Andrew Bell, Ph.D., former curator of woody plants. He recommends spring-blooming bulbs, which add color and take up little space, and, depending on how much light the garden receives, using hardy disease-resistant landscape roses and smaller flowering shrubs, dwarf conifers, or smaller ornamental grasses.

A variety of plant shapes and textures can make the space more interesting as well. Don't overlook containers, he adds, which draw attention to small planting beds. They can also hold edibles, such as lettuce, herbs, or tomatoes throughout the growing season.

A small space may appear larger if you can work in an arbor to serve as a doorway or create a winding path, rather than a straight sidewalk.

Small gardens can also benefit from "found" objects, like ornamental ceramic tiles placed on the ground or on a wall, or a small sculpture that serves as a focal point.

SMALL-SPACE PLANTING INSPIRATION

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Helen and Richard thomas English Walled Garden
enclosed by walls and hedges, it offers a variety of different garden styles from formal to informal.

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Buehler Enabling Garden
features raised beds, dramatic containers and vertical walls planted with colorful annuals.

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Farwell Landscape Garden
offers formal and informal herb gardens, a perennial border, a rock garden, an easy-to-grow mixed border, and other small-scale landscaping ideas.

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Sensory Garden
raised beds highlight fragrant and colorful plants up close.

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Circle Garden
provides examples of ways to create garden rooms and features an ever-changing display of bulbs and annuals.

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Regenstein Fruit & Vegetable Garden
presents a dramatic display of espaliered trees and small planting beds filled with vegetables and edible flowers.

 

Planting a Glass Jar Terrarium

Tim Pollak, outdoor floriculturist here at the Chicago Botanic Garden, recently taught a fun class, a glass jar terrarium workshop, with the Joseph Regenstein, Jr. School of the Chicago Botanic Garden. I went down to the production greenhouse that morning to learn how to plant a terrarium so I could share some tips with you. Follow the steps below to make your own! Need a little more direction? In the video below, we build a terrarium and give a few extra tips for success.

First, select a container such as a glass bottle, glass vase or bowl, miniature glass greenhouse, fish bowl, or something similar. Use a tightly closed, clear glass or plastic container to retain the most humidity. Open containers also work, but will require more frequent watering.

Let's build the layers (from the bottom up):

1. Start with a layer of coarse sand or pebbles, usually no more than 2 inches deep.

 

2. Cut a sheet of landscape fabric or weed barrier to fit over the pebbles.

 

3. Add 1/4- to 1/2-inch activated charcoal (available at an aquarium store) to help filter the air and water and keep the terrarium fresh, especially if it's a closed terrarium.

 

4. Use a clean, well-drained growing medium that is high in organic matter. A blend of peat moss, vermiculite, and perlite is a good choice. Soil should be slightly moistened prior to planting. If planting a desert garden, use the proper type of soil. Add about 2 inches of soil.

 

5. Select small plants that are suited to your light conditions. Add a mixture of plants with small or large leaves, short and tall in height, and other variations. Add color, either with foliage color and interest, or with flowering plants.

 

6. Add accents and ornaments to complete the look you are trying to create. Create a miniature landscape or theme.

Caring for your terrarium

Watering: Water until moistened after planting, being careful not to let water pool in the bottom where it cannot be removed. Leave the closed terrarium uncovered until the foliage has dried. A closed terrarium may not need to be watered for 4 to 6 months — look for condensation to form on the inside of the container to check the moisture level. Open terrariums need watering occasionally but not as frequently as other houseplants. Watering should be light to avoid standing water. 

Light: Keep out of direct sunlight as the terrarium could heat up too much and you could injure the plants.  Most plants suitable for terrariums prefer medium to low light. Bright, indirect sun is preferred. If you need to supplement light with an artificial light, a 100-watt bulb placed close to the terrarium or fluorescent lights placed directly over the terrarium will be helpful. Supplemental lighting should be provided 14 to16 hours per day.

Fertilizer: Generally, plants in a terrarium should not grow rapidly and should seldom need fertilizer. Do not fertilize more than one to two times per year. Use a slow-release pellet fertilizer at 14-14-14. 

Temperature: Keep terrariums in a warm location (65 to 70 degrees Fahrenheit). Avoid cold drafts as much as possible. Certain plants, such as desert plants and succulents, may prefer warmer temperatures.

Pruning: Many plants in a terrarium will gradually outgrow their limited space. Pruning will keep them in their space and often promote side-shoot growth that will help fill out the plants. Be sure to remove all trimmed vegetation from the terrarium when complete. As the plants mature, it may become necessary to remove certain plants or add others.

Feeding Your Roses

Are your roses just short of spectacular this season? Corri White, Chicago Botanic Garden horticulturist of the Rose and Dwarf Conifer Gardens, shows you best methods for feeding your roses to make them healthy, and the envy of all your friends and family.

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