Gardening with Georgia

Archive - July 2011

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Midsummer plant stress

Fri, Jul 29, 2011 at 03:14:27 PM

A weird summer weather pattern has landscape plants really feeling the heat in gardens near the coast, where rain has been irregular and sparse.

For orchid lovers, be sure to water your vandas twice a day, using a light mist in mid-afternoon if it’s not raining. Fertilize weekly, adding extra potassium and magnesium sulfate or Epsom salt (1 teaspoon each per gallon of water) to improve cell health.

At the 5th symposium of the Coalition for Orchid Species held recently at Fairchild, Hawaiian grower Roy Tokunaga emphasized the need of orchids for calcium as the real blossom boosting mineral element. He highly recommended 15-5-15 every week during the summer, “unless plants are under stress, it’s raining or humidity is very high. Then the calcium requirement doubles or triples at these times.” Which means you could be applying the 15-5-15 fertilizer twice a week now for superior plants and flowering. (If doing so, you can skip the addition of Epsom salts and potassium.)

Broad yellow bands on lower
fronds of this Phoenix palms are
signs of magnesium deficiency.

For heat stress generally, you can spray the foliage of your palms and other plants with 1 to 2 tablespoons each Epsom salt and potassium per gallon of water.

Magnesium deficiency is apparent in many Canary Island date palms around South Florida. Look for the yellow bands along the edges of the lower fronds. This is a telltale sign that you’re not using palm special fertilizer (8-2-12) containing extra potassium and magnesium.

The Institute for Food and Agriculture Services of the University of Florida recommends using kieserite four to six times a year on severely affected Phoenix palms. Kieserite is a soluble form of magnesium. The application rate is 2 to 5 pounds per large tree, 4 to 6 times a year for two years. Scatter the product under the canopy.

Regular palm fertilizer should be applied at a rate of 1½ pounds per 100 square feet of canopy or planting bed. August is a good time for a light application of fertilizer if you have been receiving rain regularly.


A peacock in the garden

Wed, Jul 13, 2011 at 05:47:59 AM

Selaginella willdenovii shines
in the rainforest.

Club mosses (also called spike mosses) had a rough time in the drought. Yet, with our high humidity and some squirts with a hose, Selaginella species can succeed until the rains become more regular afternoon events. In Fairchild’s rainforest, there’s a glorious Selaginella willdenovii. Its blue iridescent sheen makes this fern ally a wonderful addition to a shady and moist spot in the garden.  It hails from Southeast Asia. The so-called blue peacock fern or peacock club moss is a Selaginella uncinata. A red version is S. erythropus from South America.

While there are some fern allies that grow in temperate areas, most are tropical. They reproduce by spores, as do ferns, but their leaves are entirely different. Club mosses have minute leaves with a single vein in each.  The spores are produced in little spikes at the end of the leaves.  Many of these species make good ground covers because they crawl along the ground and form mats. Others, like S. willdenovii, form frond-like leaves that rise up from the ground; still others grow their leaves in rosettes.

High humidity is necessary to keep the thin leaves healthy.  Over winter and in a dry spring, my peacock fern, which is a ground cover beneath a mango tree, developed brown areas. These dead areas can be pulled away or just left, and the new branches will form over them.

A good reference for fern allies is Fern Grower’s Manual, Revised and Expanded Edition, by Barbara Joe Hoshizaki and Robbin C. Moran.






Fri, Jul 01, 2011 at 08:16:55 AM

These Livistona decora,
foreground, are among new
palms in parking area.

Visitors coming to the 19th International Mango Festival will find the lowland parking area sporting Livistona decora, Phoenix sylvestris and Veitchia species replacing the ropes used to define parking rows.

New plantings also screen the area from the Visitors Center and the Lakeside Cafe.

You’ll also notice new palms at the garden’s south entrance and the Garden Club of America Amphitheater, all donated by Manny Diaz.

The south entrance (employees’ parking area) has been given a

South entrance.

more elegant look with Bismarckia nobilis, Hyobphorbe verschaffeltii and Thrinax radiata. Grounds supervisor Ricardo Aberle has been adding to the under story of these mature palms, and soon a new sign will grace the entrance.

New royals have been added to the existing palms behind the amphitheater while two dozen coconuts have been planted inside the amphitheater.

“Down among the sheltering palms, oh honey wait for me….”