Planning the summer flower garden

Richard Bogren, Gill, Daniel J.

By Dan Gill

LSU AgCenter Horticulturist

(03/16/18) As we move into April, we can enjoy the peak blooming season of our cool-season annuals. But it’s not too early to begin to plan our summer gardens. If you have empty flower beds, you may even begin to plant summer flowers in late March in south Louisiana or early to mid-April in north Louisiana.

Thoughtful planning, carefully considered plant choices and well-prepared garden beds will produce the best results. Unfortunately, many a gardener’s enthusiastic spring efforts have turned into summer disappointment and burdensome maintenance chores.


We put bedding plants into prominently placed beds to create color in the landscape. If they are not properly maintained through the heat of summer, however, these plantings become eyesores that actually detract from the appearance of the landscape.

By all means, plant to your heart’s content. But plan your beds so the maintenance they will require can be carried out not just in spring but throughout the hot summer. Flower beds are among the highest-maintenance areas in your landscape. Do not plant more beds than you have the time or inclination to devote to their care and upkeep.

Another part of planning involves developing a color scheme. Think about the colors you want to use and their placement in the landscape before you go to the nursery. Use masses of the same color to maximize visual impact. Use colors that combine well with the background and that pleasantly harmonize or contrast with each other. Locate color in the landscape where you want to focus the viewer’s attention.

Generally, choosing a limited number of colors or variations of a single color is more satisfying than using many different colors. Let your taste be the guide; just think about it instead of randomly grabbing whatever catches your eye at the nursery.

Plant selection

It’s important to select bedding plants that will perform well here and tolerate the extreme heat of our coming summer. Also, choose plants that will do well in the sunlight of the location where you intend to plant them.

A tremendous selection of bedding plants is available for sunny areas that receive six hours or more of direct sunlight daily. Commonly available choices include angelonia, rudbeckia, periwinkle, marigold, Profusion and Zahara zinnias, blue daze, narrow-leaf zinnia, dwarf lantana, salvia, torenia, purslane, pentas, sun tolerant coleus, balsam, gaillardia, melampodium, cleome and celosia.

In shadier areas that receive two to four hours of morning sun, excellent plants to use include impatiens, wax begonias, caladiums, coleus, torenia, polka dot plant and browallia.

Check the labels on the plants you are considering to see how tall they will grow. This is very important to how you will use them. It’s not at all unusual for bedding plants to exceed the size on the tag in our area because of our long growing season and fertile soils. But the tag can be a good guide.

Bed preparation

The performance of bedding plants in your landscape is extremely dependent on how well you prepare the beds prior to planting. There are just a few key steps, but they are important.

— Remove any existing weeds. Make sure you take out the roots, especially for tough, persistent weeds like bermudagrass, dollarweed, oxalis, nut grass or torpedograss. A good alternative to hand removal is to spray the weeds with glyphosate herbicide, which is in Eraser, Roundup, Killzall, Grass and Weed Killer and other brands, 10 to 14 days prior to planting. This herbicide will kill the tops and roots of these weeds and does not leave a harmful residue in the soil. Do not get it on the foliage of desirable plants nearby, however.

— Turn the soil thoroughly. You may use a shovel, spade, garden fork or tiller, but make sure you dig down at least 8 inches. Do this when the soil is moist but not wet.

— Spread a 2-to-3-inch layer of organic matter such as compost (best), peat moss or aged manure over the area. Sprinkle with a general purpose fertilizer following label directions. Thoroughly incorporate everything into the bed.

— Rake the bed smooth. It should appear slightly raised. This is good because it improves drainage.

— Alternatively, you can build a raised bed about 8 to 12 inches deep and fill it with a blended topsoil or garden soil mix.

— Lay out the individual plants at the proper spacing and in the arrangement you desire, and then plant them. The top of the transplant’s root ball should be level with the soil of the bed.

— Mulch. I mean it. This is very important to minimizing your future maintenance. The mulch suppresses weeds, maintains soil moisture and keeps the soil in the loose condition you worked so hard to achieve. A 2-inch layer of leaves (oak leaves are great), bark, pine needles or almost anything along those lines will work well.

— Water thoroughly to settle everything in, and you are done.

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Melampodium is a compact, tidy annual that blooms all summer with chunky yellow daisies. Photo by Rick Bogren/LSU AgCenter

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Little Ruby alternanthera is a great, low-maintenance plant to add color to your landscape. It offers an alternative to traditional blooming bedding plants. The beautiful foliage in shades of burgundy and purple adds rich color to the landscape and is consistently attractive throughout the season. LSU AgCenter file photo by Allen Owings

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An alternative bedding plant to consider instead of impatiens is torenia, also called wishbone flower. Torenia is a great, underused shade-performing plant. LSU AgCenter file photo by Allen Owings

3/16/2018 7:03:25 PM
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