Mary Ferguson, Singh, Raghuwinder, Strahan, Ronald E., Fontenot, Kathryn, Kirk-Ballard, Heather
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We prune plants for a variety of reasons. Sometimes, we prefer or feel obligated to maintain a certain appearance, such as a raised canopy on a plant that naturally produces growth near the base or a small number of trunks on a potentially multitrunked plant.
Often, we prune because a plant was put in a place for which it eventually got too large — close to a house, under a window or power line, etc. This type of pruning is largely preventable by attention to mature plant size and placement prior to planting.
One reason to train young trees, particularly, is so they’ll have good structure and not have the narrow crotch angles and included bark that make branch attachments weak. If you’ve ever wondered why Bradford pear trees tend to break apart in storms, this is why.
Removing crossing limbs to prevent damage and removing already damaged or diseased parts of plants are other reasons to prune.
When it comes to fruiting plants, we may prune to make picking easier, to increase sunlight penetration and air movement, and to improve fruit quality.
There are several things to consider when deciding if, when and how to prune. One of the primary considerations regarding when to prune is flowering time and, relatedly, whether a plant flowers on new growth (the current season) or old growth.
Ornamental plants that bloom in the late winter and early spring generally bloom on shoots that grew in a previous season. Many of our azaleas, like the southern Indica hybrids (Formosa, George Lindley Tabor, etc.), are poster children for this. To avoid sacrificing blooms, these should be pruned after flowering.
I’ve been asked how late is too late to prune azaleas. The end of June or first of July are sometimes mentioned as a cut-off dates, after which flower buds are likely to be forming for the following year. However, I don’t know exactly when flower bud formation starts here in southern Louisiana. This stage of bud formation is something that happens within the plant — not something we can see on the outside of a branch.
Rather than putting off pruning until the end of the window, if you need to prune your azaleas, you should go ahead and do it soon after blooms fade. This gives plants more time to recover before weather gets hot.
Other plants that bloom on old growth and should be pruned soon, if needed, include camellias, primrose jasmine, Carolina jessamine and bridal wreath spirea.
Crape myrtles, chaste trees (vitex) and American beautyberry are examples of the opposite situation. They produce blooms on new shoot growth, so they can be pruned in late winter, while dormant, without removing flower buds.
Some groups have species with both types of plants. Among the hydrangeas, mophead or “French” hydrangeas generally bloom on old growth, although there are exceptions, such as the Endless Summer series. Mophead hydrangeas are unusual among the old-growth bloomers in that they bloom relatively late in the season. Oakleaf hydrangeas bloom on old growth as well, while panicle hydrangeas, like Limelight, bloom on new growth and can be pruned in late winter.
Many roses bloom on new growth, which is why they’re often pruned in late January or early February. There are some roses, though, that bloom once per year on old growth and should be pruned after flowering. These include the Cherokee rose and Lady Banks’ rose.
Mary Helen Ferguson, Ph.D.
Associate Extension Agent
You don’t need a large yard or a lot of space to create a beautiful garden. You can create beautiful planters or containers that fit any space with limitless plant combinations that bring beauty and joy to wherever you call home.
There are plenty of options to choose from when it comes to the size, shape and color of containers and planters — hanging baskets, window boxes, small and large containers for combination plantings, single plant containers and clusters of pots. Your options for the plants themselves are plentiful and diverse, too.
To create a beautiful container design, begin by choosing a container that suits your spatial needs. Most garden centers, retail nurseries and online shopping venues offer many types.
Next, choose the plants and arrange them in a design of your choosing. Keep them looking good until you want to change the design.
One of the great advantages is that you can change these out. Year after year, you can play with the plant combinations, colors, textures and themes.
A combination planter typically has what is known as a filler, a thriller and a spiller. If you haven’t heard these terms yet, let me explain them to you.
The thriller is the plant that is main attraction of your container planting. It will be the focal point of your design. Choose a plant that has some height and a striking flower form or color.
The filler is just as the name suggests. Use these plants to fill in areas to create a fuller look in the arrangement. Fillers are medium-sized plants, typically in a mounded form, that make up the bulk of the plant material in the container. You can choose just one type of plant for focal impact, or you can choose several different plant types of similar sizes.
Spiller plants are the trailing, cascading plants that flow over the sides of the containers and complete the arrangement.
When choosing fillers and spillers, a good rule of thumb is to use an odd number of plants — three, five, and seven and so on.
Symmetry brings a good balance to beginning designs. Although it is not required to have an equal number of similar or identical plants on each side of the focal point, it does bring a visual balance to the arrangement.
Be sure you bring different textures into the container planting and design. Add fine-, medium- and coarse-leaved plants. Use tall pieces that bring height for the focal point; shorter, mounding species en masse; and low-growing spiller plants to soften the edges of the container planting.
Lastly, use proportional sizes to match the container. For large containers, use larger plants; use smaller plants in small containers. The rule of thumb is that the tallest plant should not be taller than 1 to 2 times the height of the container.
Now is the fun part: picking the plants. Be sure that you use season-appropriate plants. For example, if you are creating a design for the summer, make sure you are using heat-tolerant, warm-season annuals and perennials.
Most trees and shrubs will be fine throughout the seasons, but be sure to use evergreen selections unless you plan to rotate them out with the seasons as you do with your annuals and perennials.
Here are a few suggestions of Louisiana Super Plants for each category for medium-sized containers.
Thriller plants: Suncredible yellow sunflower, Flamethrower coleus series, Fireworks pennisetum, Senorita Rosalita cleome, Intenz Classic celosia, Flutterby Tutti Frutti buddleia, Camelot foxglove series, Diamonds Blue delphinium, Jolt and Amazon dianthus series.
Filler plants: Beacon impatiens series, Babywing begonia series, Serena and Serenita Raspberry angelonia, Mesa gaillardia series, Butterfly and Lucky Star pentas series, Sorbet viola series, compact varieties in the Sunpatiens impatiens series, Kauai torenia series.
Spiller plants: Mini Vista Indigo and Vista Bubblegum in the Supertunia petunia series, Homestead Purple verbena, lemon sedum.
Heather Kirk-Ballard, Ph.D.
Consumer Horticulture Specialist
Heather Kirk-Ballard, Ph.D.
Consumer Horticulture Specialist
Enjoy the Garden,
Kathryn “Kiki” Fontenot, Ph.D.
Vegetable Gardening Specialist
Lawn |
Number of fertilizer applications/year |
Recommended months |
Bermudagrass |
3 |
March/April, June, August (optional September) |
Centipedegrass |
1 to 1.5 |
April and possibly June at ½ fertilizer rate |
St. Augustinegrass |
2 to 3 |
April, June, August |
Zoysia |
2 |
April and July |
Ron Strahan, Ph.D.
Weed Scientist and Turfgrass Specialist
Raj Singh, Ph.D.
Associate Professor
Director, Plant Diagnostic Center