Gardening with Georgia

Archive - December 2012

« Back to front

A rare sight

Wed, Dec 26, 2012 at 02:49:24 PM

Female flowers of Alvaradoa

One of South Florida’s rare trees, Mexican alvaradoa (Alvaradoa amorphoides) is blooming at the Garden in plot 43, which is near the Visitors Center. This small tree is dioecious, with male and female flowers on separate trees. Male flower spikes are long and dangling; females are shorter and fatter, with each small green capsule being an ovary. The tree is one of the host plants for the Dina Yellow butterfly (Pyrisita dina). The other host is bitterbush, (Picramnia pentandra). Alvaradoa ranges from Mexico through Cuba to South Florida. The trees are able to endure in dry conditions; I grow mine without twice-weekly irrigation. It sits in the far corner of the back yard, along with a few other native plants, all of which must compete with roots and shade from a neighbor’s Ficus benjamina hedge. Alvaradoa grows fairly rapidly, with long, skinny branches and compound leaves, and a taller-than-wide silhouette. If you plant this rare tree, a rare butterfly may find it.



Awesome in the right light

Thu, Dec 20, 2012 at 08:17:03 AM

Gloxinia sylvatica.

Seeing red (or orange) at this time of year? We’re not thinking poinsettias here, but they are in profusion everywhere we look. During a morning walk through the Garden we were struck by the light on two plants: Gloxinia sylvatica and Juanulloa mexicana.

Each offered an expression of nature’s magic with chemistry: plant production of secondary metabolites, such as anthocyanin and flavonoids that create red and yellow pigments. More often than not, we take these things for granted. Occasionally we would do well to stop and be awed.

Juanulloa mexicana.


Starring a Winter Fruit

Tue, Dec 18, 2012 at 07:12:07 AM

Averrhoa carambola 'Thai Knight'.

Carambolas (Averrhoa carambola) are in full of fruit now and the branches of our home trees are bending beneath their weight. Carambolas, or star fruit, come from Southeast Asia where, says tropical fruit expert Jonathan Crane, they have been grown for centuries. The cultivar called ‘Arkin,’ which came from Malaysia, was introduced to South Florida in 1973. I remember interviewing Morris Arkin, who grew the seeds in Coral Gables. Arkin also developed a macadamia nut tree.  A carambola called Golden Star was developed in Homestead in 1965, and Hawaii has developed a number of cultivars as well. The Arkin proved the hardier shipper. ‘Thai Knight’ is a cultivar named for Bob Knight with the USDA Subtropical Research Station in Coral Gables. It is a deeper yellow than the ‘Fwang Tung.’

In our soils, the trees require fertilizer applications every three months as well as the addition of iron and micronutrient sprays to keep the compound leaves green. They like regular irrigation. Carambolas can reach 20 to 30 feet and they have a rounded crown. They produce flowers on the twigs and branches, carrying fruit there as well. Shaking a heavily loaded branch will reduce the weight by simply causing fruit to drop. The fruit is either sweet or tart, and the sweet ‘Fwang Tung’ variety is great for eating fresh. A refreshing drink can be made of carambolas; they can be sliced and used in salads. Schnebly’s Winery in the Redland makes a carambola wine that they say tastes like a Pinot Grigio.


Winter Pests

Fri, Dec 14, 2012 at 01:39:41 PM

Stippling on leaves.

When hot, or even pleasant, and dry weather descends on us,

Red spider mites.

there are some things to watch for in the garden. One is red spider mites. These tiny red insects hide out on the bottom of leaves and suck cell sap, creating a stipple effect on the top of the leaves. I am finding them all over the passion vine Passiflora incarnata. They also love soft-leaved orchids. Once you see the stippling, you may need a hand lens to observe the insects on the underside of the leaf.

Treatment is easy: a hard spray of water, or a mix of 1 tablespoon liquid dish detergent that contains no perfumes and 1 tablespoon vegetable oil or horticultural oil in a gallon of water. Spray the undersides of the leaves well. Try the water first.

A ladybug will eat them.
Golden oleander aphids on milkweed.

Oleander aphids have been appearing in globs on my milkweeds. They are golden with black appendages. They not only are on the stems, but leaves and seedpods. Ladybugs and their larvae eat them, while parasitic wasps lay eggs in them, which turn them brown and kill them. If you are too impatient for the beneficial insects to show up, use insecticidal soap to suffocate them.