Q: How do I choose and care for perennials in my Gulf Coast garden?
A: Although I succumb to the lure of the floral displays at the big-box stores each spring, I must admit that watching the perennials in my yard wake up is a more rewarding experience. Maybe the best part is that after the initial investment, perennials are practically free. Most perennials along the Gulf Coast are easy to grow if you adhere to a few simple rules.
1: Know your zone and when to plant
Some of the plants considered annuals for which we shop at the big-box stores are actually perennials in warmer climates. This explains why a beautiful yellow mandevilla that I treasured for some years died during one particularly cold winter. I had bought it labeled as a perennial, but as an inexperienced gardener at the time, I had failed to check my growing zone. I have since learned that I can keep my frost-tender perennials, including my mandevillas (Mandevilla spp.) and allamandas (Allamanda cathartica), alive by covering them or putting the ones growing in pots in the garage when temperatures plummet.
For best results, plant perennials in the fall to give them a chance to establish their roots before they have to contend with the not-so-gentle summers along the Gulf Coast. It is also good to do a soil test to check for compatibility. This can be done through the local county extension office on Schillinger Road.
2: Know your desired colors
Know what colors will enhance your garden, when and how long the perennials you plant will bloom and how large they will grow.
If I could only have one plant in my yard, it would be purple Muhly grass (Muhlenbergia capillaris). I love it for its beautiful, diaphanous, pink feathery plumes that burst forth in the fall. When many of the other flowers are pretty well spent, Muhly grass is still showing off.
Take note that the contents of a pot that tucks into a small space in the car on the way home from the nursery can engulf a major section of a flower bed in a season or two. Muhly grass is one of these, but if anything has to take over in my flower bed, please let it be this beautiful plant.
It is also worth remembering that some perennials will die back, leaving a blank space in the flower bed after the cold weather sets in, so think in terms of putting these near plants that can brave drops in temperature if a blank space in winter is not in keeping with your general landscaping plan.
3: Check optimal growing conditions
Try to plant your perennials where they will flourish. If they like full sun, then so be it. If deadheading prolongs blooming, get out your clippers. Fortunately, many of the truly lovely perennials along the Gulf Coast are drought tolerant and can handle heat and humidity. Many of the perennials from which we have to choose are virtually maintenance free after they are established in your garden.
If you have a serious trouble spot and want a nice ground cover, consider wedelia (Wedelia acapulcensis). Its deep green leaves and abundant daisy-like flowers are a nice contrast with taller plants, although you will have to monitor it or it will extend far beyond its intended borders.
To be safe, plant it in a flower bed that is bordered on all sides by concrete. When I gave a cutting to one of my friends for an area where she couldn’t make anything grow, it became so profuse that she said the only way she got rid of it was to move. Blue daze (Evolvulus glomeratus) is also a lovely perennial ground cover, and, unlike wedelia, it is not invasive. It is, however, cold sensitive and may need to be covered if temperatures drop.
4: Pay attention to pests
If you have a garden, be it vegetable or flower, you will have pests. However, the best defense against garden pests is a healthy plant, and that is achieved most effectively through proper use of water, fertilizer and mulch. Should you find it necessary to spray pests, using an insecticidal soap that contains natural ingredients harmless to people and pets is the place to start. These can be purchased at any garden center, or you can make your own version with simple kitchen dish soap. If the soap doesn’t work to your satisfaction, it may be worth taking a sample of the pest or damaged plant part to the county extension agent for advice.
5: Prune judiciously
If you prune before really cold weather sets in, you run the risk of encouraging your perennials to produce new growth shoots that will get “burned” during subsequent cold snaps. You can cut back any dead, dying or damaged parts of your perennials at any time. If you want to provide seed heads for foraging birds, you’ll want to wait until late winter to prune coneflowers, heliopsis and black-eyed Susans.
When pruning, cut perennials to within two to three inches of ground level. In addition to an annual pruning, some perennials, such as butterfly bush (Buddleia davidii), may benefit from additional, less-vigorous pruning during the growing season to avoid developing an undisciplined and gangly appearance.
For expert advice about selecting and growing perennials along the Gulf Coast, check “Easy Gardens for the South” by Cotton, Crawford and Pleasant. Email your questions at CoastalAlabamaGardening@gmail.com.