David W. Marshall
Summer is a challenging time in the North Florida garden, yet it can be a very rewarding time, too. The difference between getting discouraged and in enjoying the summer garden is in knowing what plants to grow.
Our summer heat and humidity is too much for some of the plants that we see gardeners growing through the summer in other parts of the country. Yet many garden plants which have their origins in tropical areas of the world thrive through our summers, and our winters are mild enough that these plants re-sprout from the ground late each spring and act as perennials here.
We do not want to use non-natives that are invasive and spread into woodlands or areas where we don’t plant them. But we can plant non-natives (exotics) that are well-behaved garden plants. Many of our common garden plants, azaleas for example, are exotics.
The key to success in the garden is to use plants that are well-suited to the site and to our weather conditions.
In my garden right now, Turk’s cap, native to Texas, Mexico, Central America, and northern South America, as well as parts of the West Indies, has been flowering since spring. Thryallis, another central America native, is just starting to bloom. South African natives, plumbago and Bauhinia galpinii, also do well for us.
Firebush, native to all the Americas, has recovered from the winter’s cold damage and is about ready to start flowering. Don’t forget the South American native, angel’s trumpet or Brugmansia, with its large, fragrant trumpet-shaped flowers.
Powderpuff bush (Calliandra spp.), a Central America native, has also proven to bounce back from our winters fairly well and provides bright red powderpuffs of flowers summer through fall.
The lime green and yellow foliage of variegated shell ginger, native to eastern Asia, brightens the summer landscape and is very useful in shaded to partially shaded spots. Coral butterfly ginger is about to begin its flowering period also.
Hydrangea, with its blue, pink, or white flowers, is good for shaded areas. Landscape roses, such as ‘Knockout’, ‘Flower carpet’, and ‘Drift’ roses provide continuing blooms in sunny areas.
Most of these perennials will continue providing color well into fall.
Perennial color and natives
All of the aforementioned are shrubby perennials that require a little space. If you want lower-growing color for a bed, consider trailing torenia, zinnias, pentas, Sunpatiens, coleus, melampodium, African bush daisy, and society garlic.
Good native perennials include purple coneflowers, Rudbeckia, and Stokes’ aster.
All these colorful plants that thrive through our summers and into fall can be planted now, in the midst of summer. If you don’t have some of them, you’re missing out on a colorful time of year!
Most flowers will require a good bit of sun, but Sunpatiens and regular impatiens do well in shade as well as the colorful foliage plants variegated shell ginger, coleus, caladiums, and even to a degree, croton.
Lawns are thriving now that the summer thunderstorms have begun, providing adequate water and additional nitrogen.
Do not fertilize now, at least not with a nitrogen fertilizer. Wait until late August or early September to see if your lawn needs it again. Centipede lawns may not. Other types of grasses probably will need the late fertilization at that time with a fertilizer that contains equal amounts of nitrogen (the first number) and potassium (the last number) and no phosphorus (the middle number).
Keep your lawn mowed regularly and be sure the mower blade is sharp. Using a dull blade shreds the grass, resulting in browning and often stressing the grass.
Presently there is not much going on as far as lawn pests. But as the summer advances be on the watch for common lawn pests such as chinch bugs and gray leaf spot in St. Augustine grass.
Tropical sod webworms can quickly eat large areas of any type of lawn in late summer. You usually just see the damage and not the caterpillars because they feed at night. Control of pests is much easier if you spot them early.
Having had a busy spring, I forgot to broadcast fire ant bait to my property. Recently I noticed new fire ant mounds starting. But it didn’t take long to broadcast the fire ant bait to all the sunny areas of my property using a small hand spreader such as you use to broadcast seed.
This keeps fire ant mounds to a minimum for approximately six months. If you choose to just treat fire ant mounds as they pop up, avoid the common mistake of applying a bait product, such as Amdro, directly on top of the mound. Instead, follow the label directions and apply the bait around the mound, not disturbing the mound as you apply it.
Shrubs are putting on a lot of new growth now. Keep them pruned to the size you want them. Though you may be accustomed to just using hedge shears to do this, realize that you occasionally need to take the extra time to go into the interior of the shrubs and selectively remove some of the branches, opening up the canopy and allowing light to better penetrate.
If you do not do this, and just continually shear the surface, you will end up with a shrub that has no foliage on the interior. A little damage to the exterior foliage will leave large, gaping holes.
Planting and mulching
Now, while we are having summer rains, is a great time to plant shrubs and trees. This is crape myrtle flowering season. If you plant new crape myrtles, be sure to select varieties that you won’t have the necessity to top as they reach their mature height.
There are some excellent lower-growing crape myrtles available in garden centers. Consider them as “low-maintenance” crape myrtles, as the slower growth rate will reduce pruning requirements.
Stay on top of mulching this summer. Pine straw, our most commonly used mulch, breaks down over time and you will simply need to add new pine straw on the surface to maintain a two-inch thick layer all year. There’s no need to remove the old mulch.
Weeds and caterpillars
If you have a lot of weeds in the mulched areas, you may wish to spot-treat carefully with a glyphosate herbicide, or hand-pull the weeds, a week or so before putting down the fresh mulch. Maintaining an adequate layer of mulch makes weed control in beds much easier. It is an often-neglected part of landscape maintenance that’s really very easy to do and instantly makes everything look better.
Oleander caterpillars have been prevalent the last couple of summers, so be on the watch for them this summer if you have oleanders. If you ignore them, they can just about defoliate oleanders and can put a quick halt to the flowering.
Visit your local garden center for an insecticide to control them and a sprayer, such as a hose-end sprayer, that will reach the tops of the plants.
Heat tolerant vegetables
You may still have some heat-tolerant vegetables such as okra, eggplant, peppers, Lima beans, southern peas, and sweet potatoes in the garden now.
Keep the garden area clean, removing dead and dying plants from your spring planting so as to not build up greater pest populations and removing weeds around the area.
In August you can begin to add more plantings of Lima beans, snap beans, cucumbers, peppers, pumpkins, summer squash, and tomatoes. In regard to fruit, we’re just heading into fig season. Pick daily, trying to stay ahead of the birds and squirrels.
Take advantage of the summer growing season to plant new fruit trees, especially citrus which will benefit from the added benefit of the extra growth and hardiness before going into the winter.
By avoiding the midday sun, after almost 46 years of living in Tallahassee, I’ve about accustomed to gardening in the heat! But I have not accustomed to the mosquitoes and ticks.
When I am working outdoors, I use a DEET-free insect repellent that works well against the mosquitoes and ticks. I recommend that you use a repellent that works for you, too, as the mosquitoes and ticks are terrible this year, and both can carry diseases that affect humans.
Also, constantly keep bird baths and other mosquito breeding areas clean and try to keep underbrush cut in wooded areas to reduce the tick problems.
David W. Marshall is a landscape consultant with Tallahassee Nurseries and an Extension Agent Emeritus with UF/IFAS Extension Leon County, an Equal Opportunity Institution. For gardening questions, email the extension office at [email protected]
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