Gardening with Georgia

Archive - April 2011

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A feast for the eyes

Wed, Apr 27, 2011 at 09:37:41 AM

With each passing spring, our Oncidium sphacelatum
becomes more beautiful, perched in a Tabebuia.

This dancing lady orchid, Oncidium sphacelatum, is a splendid example of how orchids thrive in trees. The three-foot flower spikes are loaded with hundreds of tiny yellow flowers that dance on the winds of Spring.

Fertilized every two weeks with 15-5-15, this lovely specimen has large pseudobulbs to retain water, and it is seldom given extra irrigation (unless I happen to think about it). For ease of care and great reward, it's an orchid at the top of my list.


Flowers worth finding

Fri, Apr 22, 2011 at 03:20:29 PM

Four plants are blooming now at the Garden that you should come and see.

Napoleon's hat.

One was noticed by Jason Lopez in the horticulture department, who planted it five years ago. This is Napoleonaea imperialis, or Napoleon’s hat, and Jason sent an email to the staff saying it’s worth a trip to plot 45 to find it. In his email Jason wrote, “This plant comes from west Africa and is found in the rainforest under story, where the twigs are used as chew-sticks, the fruits sugary pulp is used for desserts and the roots are used medicinally.”

Scott Zona has one of these West African plants in the Wertheim Conservatory at FIU and posted a couple of lovely pictures of it in the past. The corolla is reflexed, Zona pointed out, and the whorls are stamens. A flat stigma is found in the center. The flowers are cauliflorous, growing directly on the branches, so you may not see them initially when you find the plant.

There is another flowering tree you should seek out in the Conservatory.

Pride of Burma.

Amherstia nobilis, or Pride of Burma, has but a single pendant cluster of pink flowers, but the flowers are so wonderfully elegant that some people consider Amherstia the most beautiful flowering tree in the world. Two of its petals are tipped in yellow and an upright, larger standard petal is colored with band of yellow as well as discreet touch of magenta and some bars of darker pink.  Ernesto’s Good Earth was the first nursery to introduce the tree to South Florida commercially several years ago, and it was so delicate and cold tender that the tree had its own tent to protect it over winter.

Brownea sp.

Another wonderful flowering tree is in the genus Brownea. Labeled simply Brownea sp. (species), the specimen is next to the offices of the horticulture staff. Softball sized clusters of scarlet flowers throw out many golden-tipped stamens. It’s quite a special show.

Is this jacaranda prettier than
the Pride of Burma?

But even the Jacaranda cuspidifolia near the Bailey Palm Glade seems more beautiful than usual this year, showing off deep blue flowers that are abundant all around the canopy.

So take a look at these wonderful plants and decide if any of these is indeed the most beautiful in the world. Or offer your own nominee.


Noble live oaks

Mon, Apr 18, 2011 at 03:36:00 PM

Live oaks, such as this one at Maclay Gardens
can live hundreds of years.

 Majestic is a description usually reserved for mountain peaks and California redwoods, but I vote to attribute the adjective to the native live oak as well. Truly grand live oaks are few and far between in South Florida, given our development and storms. There are a couple of wonderful live oaks at Fairchild that have been graced with epiphytes in addition to their natural coating of resurrection fern; there’s a splendid oak on San Remo that pulls my car by it often just so I may admire it; there’s the big one at the Deering Estate at Cutler, which is the center of an Indian burial site. The Council Oak on the Seminole reservation in Hollywood still stands near US 1 and Stirling Road, albeit surrounded by a parking lot.

Live oaks can reach 80 feet tall and 120 feet wide. Their limbs want to grow horizontally, and lower limbs will touch the ground and then turn upright.  The city of Orlando has allowed the oaks about Lake Eola to retain their horizontal limbs.

I saw several majestic live oaks last weekend at Alfred B. Maclay Gardens State Park in Tallahassee, and marveled at their girth and the reach of their branches. The Maclay oaks are draped in gauzy Spanish moss, as are many of the garden’s trees, and this creates a lovely silver sparkle in sunlight.

Here in South Florida, our live oaks (Quercus virginiana) are nearly evergreen, dropping leaves briefly in spring before acquiring new ones. The flowers are wind pollinated, and small acorns are produced in the fall. Acorns were so abundant last year that they created what is called a mast year, thought to be an effort on the part of the trees to have some nuts sprout and make it to maturity before squirrels and birds can eat them all. The nuts began falling in September and still were pinging on the metal roof in late January.

With deeply furrowed dark gray bark, live oaks offer myriad insects places to hide, and that draws insect-eating birds, such as warblers and vireos. The oak also is a host for the White M Hairstreak butterfly, the Red-banded Hairstreak and Horace’s Duskywing butterfly.

Oaks cast a light shade that's perfect for orchids, ferns and bromeliads. They're thought to be slow-growing, but if you fertilize with a palm special they will grow surprisingly fast. A fern-y groundcover will allow the fallen leaves to serve as a natural mulch. 

It's a truly noble tree, and should be given the space and reverence it deserves.





Is that thing really a flower?

Wed, Apr 13, 2011 at 07:01:00 AM

Aristolochia is a genus of vining plants that produce some of the most peculiar flowers imaginable, if it weren’t possible to say that about orchids, too. And like orchids, Aristolochia flowers have male and female parts in the same organ, called a gynostemium (or the column in orchids).

Aristolochia littoralis with one
open flower and buds on right.

There are no petals on an Aristolochia flower, but the whole thing that can resemble a Dutchman’s pipe or a pelican or a number of other odd shapes, is a calyx, or fused sepals. It swells and curves and ends, in Aristolochia littoralis, in a maroon and cream-colored hood. In her book Tropical Flowering Plants, Kirsten Llamas says, “commonly cultivated flowers suggest silk paisley handkerchiefs attached to a drain pipe.”

The vines in good soil (with organic matter added) are growing rapidly now, and a number can be fairly aggressive, but the flowers are so unusual looking that it’s worth the trouble it takes to cut them back in the fall.

Many of the species contain a toxin that is carcinogenic. But, for whatever reason, swallowtail butterflies have selected aristolochias as their host plant. The caterpillars devour the toxin along with the leaves and presumably become bitter tasting to predators.

There are several species in the Garden, including Aristolochia

 A. passiflorifolia, a tiny flower,
in the butterfly garden.

passiflorifolia, which comes from Cuba and the Bahamas and has leaves like passion vines. These flowers are really bizarre with appendages sprouting hair-like whiskers from the end of the calyx.

Flies and insects that are lured into the mysterious opening to the pipe find they cannot climb back out because of backward facing hairs, so they toss and tumble around until they fertilize the flower. The hairs then die and out go the insects.

Look for pipe vines on the vine pergola and the butterfly garden. Follow the swallowtails.



Desert roses are flourishing

Thu, Apr 07, 2011 at 06:51:11 AM

Adenium multiflorum flowers have yellow throats.
Plants are spectacular right now.


Adeniums, or desert roses, have fat caudices and weird, elongated branches, but they produce beautiful flowers. Adenium multiflorum has been quite the star for the last few weeks, blooming in front of the Gallery building. It is an African species, ranging from KwaZulu-Natal in South Africa to Zambia in the west of Africa.  This slow-growing relative of the oleander does well in South Florida,

Striped throat on this hybrid.

providing it has excellent drainage. The leaves are somewhat bunched at the ends of the tentacle-like branches. Its close relative, Adenium obesum, is found from Ethiopia and the Arabian Peninsula to Tanzania. As its name suggests, it gets a really paunchy base.

Much hybridizing of adeniums has been done in Thailand and Vietnam, and several of our cultivars at home have come from there. We have flowers with stripes, white tinged pink, double forms, and deep red flowers. There are white

A deep red flower is striking.

and peach flowers as well, but they’re not in our collection yet.

For plants in containers, I use a light sprinkling of controlled-release fertilizer. I grow several in a bed planted with cycads and pachypodiums, all of which like the same hostile environment of sand and fill covered with a leafy mulch. These plants hate to be over-watered in winter.

This double form is one of the Thai hybrids.


Laurel wilt disease

Mon, Apr 04, 2011 at 01:03:27 PM

Our native red bay tree (Persea borbonia) is a primary host plant for the Palmedes Swallowtail butterfly. The fruit also is eated by deer, songbirds, black bears and wild turkeys.

Red bay is related to two other native trees, swamp bay (Persea palustris) and lancewood (Ocotea coriacea). These trees are in the laurel family, along with avocado (Persea americana).

All of them are vulnerable to a disease that has spread from South Carolina down the coast and into Miami-Dade County.

The fungal disease is killing swamp bay trees along Krome Avenue, between Kendall Drive and Tamiami Trail, according to Alejandra Castro-Nunez of the Miami-Dade County Consumer Services Department.

The disease is spread by an Asian ambrosia beetle, first found in this country in 2002. It is apparently attracted to the aroma of these laurels and when it invades the trees, it introduces the fungus. Leaves wilt, but often stay on the branches. New shoots appear, but they also die, and eventually the trees are killed.

Work is under way to determine the best way to control the beetle and the disease. According to Castro-Nunex, a fungicide called Alamo can treat redbay trees only, but must be injected using special equipement.

The Florida Department of Agriculture and Consumer Services has a Website with significant amounts of information on the disease and the beetle. Go to and scroll down to  Plant Industry, under the heading Divisions. Click on it, and you'll find the link. Another online resource is

If your red bay, lancewood or avocado show symptoms, contact the Division of Plant Industry at 1-888-397-1517.