Chicago Botanic Garden

What's in Bloom

What's in Bloom — Highlight 01.25.13

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Calamondin orange (xCitrofortunella mitis) can be found in the Semitropical Greenhouse.

x Citrofortunella mitis is commonly known as calamondin orange, and as the "x" in front of the genus name denotes, it is a hybrid between species in two different genera — an oddity in the plant world. Citrus reticulata (a tangerine) was crossed with Fortunella margarita (the Nagami kumquat) to create a small fruited hybrid with a loose skin and very bitter pulp, whose juice can be used like lemon or lime juice. This hybrid of Philippine origin can survive a few degrees of frost, which is why it is featured in the Semitropical Greenhouse.

All types of citrus grow best in full sun and warm temperatures. Flowers are typically pollinated by honey bees, and the resulting orange blossom-scented honey is highly prized. Somewhat drought-tolerant once established, calamondin oranges will need frequent watering if grown in containers.


Rondeletia leucophylla is often sold under the name of Panama rose, even though it is actually a native of Chiapas, Mexico. This bushy, large shrub produces masses of pink flowers virtually all year when planted in the ground in a conservatory. Both hummingbirds and butterflies are attracted to the flowers, which, interestingly, don't become fragrant until after the sun goes down — suggesting that it may be pollinated by moths as well.

Panama rose can be grown as a container plant, or in the ground in a frost-free conservatory. Grow in full sun in a setting with moderate moisture.

Panama rose (Rondeletia leucophylla) is in the Tropical Greenhouse near the date palm.


Pink Sapphire No. 4 orchid (Dendrobium Burana 'Pink Sapphire No. 4') produces spikes of brilliantly colored pink flowers in winter. This cultivar is one of the 'cane orchids' that produce thickened pseudobulbs whose leaves sometimes drop before the flower spike begins to grow from near the end of the cane.

The genus Dendrobium is one of the easiest for Chicago-area gardeners to successfully grow and reflower in their homes. Grow indoors in bright light, in a free-draining media (pumice, coarse bark, or orchid potting soil), and water two to three times per week.

Pink Sapphire No. 4 orchid (Dendrobium Burana 'Pink Sapphire No. 4') is in the Tropical Greenhouse, on the east orchid tree, near the bananas.


Cutleaf acacia (Acacia cultriformis) produces brilliant golden clusters of flowers from the terminal (tip) and axillary (side) buds in late winter/early spring. The leaves are solid, not divided (unlike most acacias) and are an attractive glaucus (bluish cast). This acacia requires full sun and well-drained soils in a frost free climate, and dislikes transplanting, so young seedlings should be moved to their final location in the garden or in containers early. Like other members of the pea family, this species plays host to microorganisms that return the favor of a free meal by making atmospheric nitrogen available to the acacia.

This plant is used regionally to make honey; acacia honey is a bit darker than clover honey, but it has a fragrance that is highly desirable.

Cutleaf acacia (Acacia cultriformis) is in the Arid Greenhouse, behind the agaves.


During what is winter in North America, spider aloe (Aloe x spinosissima) produces a profusion of unbranched spikes of brilliant orange-red flowers — a favorite of hummingbirds in its native growing region of South Africa. This hybrid will tolerate temperatures down to 25 degrees Fahrenheit for short periods of time, but it grows best in full sun, in frost-free environments with well-drained soils.

The specific epithet of this cultivar refers to the abundance of blunt-tipped spines along the leaf edge.

Spider aloe (Aloe x spinosissima) is in the Arid Greenhouse near the base of the Saguaro cactus.