Unlike other areas of the country, South Florida gardens flourish during the winter months. “Winter is much drier, has a much larger palette of unusual flowers to successfully grow, and is the right season to grow any vegetable you wish,” says Allen Sistrunk, director of Mounts Botanical Garden in West Palm Beach. PBI.com spoke with Sistrunk about the ins and outs of winter gardening. Have more questions? Mounts’ Master Gardener helpline is awaiting your call.
PBI.com: What key factors should South Floridians keep in mind when deciding what to plant in their winter gardens?
Sistrunk: Winter is normally our dry season, and having your irrigation system in great working condition is essential. We might think since it’s cooler in winter that irrigation is not as important, but in our climate plants are actually growing year-round and can be stunted, weakened, and even perish from lack of adequate water. This is especially important for newly planted flowers, shrubs, and trees that need a good year of ample water to properly establish. Also, fresh pine-bark mulch will not only help greatly conserve moisture but also provide extra nutrition and a weed barrier for those pests that never cease growing in South Florida.
What’s your top winter gardening tip?
Always observe the “right plant, right place” guideline, meaning sun plants in full sun, shade plants in light shade—and remember the winter sun is much less intense than the warm season. The best thing about winter gardening here is there is hardly anything that will not thrive during our winter months, including delphinium, crystal blue lobelia, foxglove, and English daisies—but these beauties will certainly perish by mid-May, if not sooner.
What nighttime threats to their gardens should South Floridians prepare for in the winter months?
We have occasional chilly nights in late December, January, and early February, but my advice is to let the fittest survive and don’t try and protect from the cold. Sometimes our attempts to protect from the cold backfire and do more damage than good. If you have potted and hanging orchids as well as other super tropicals in containers it is advisable to bring them into shelter on the very coldest nights, below 45 degrees Fahrenheit.
What vegetables can be grown in winter?
There is hardly a vegetable, herb, or spice that will not thrive in Palm Beach County during the winter as long as it receives enough light and water and, of course, is not planted in pure sand. Lettuce grows astoundingly easily, and many successful crops can be grown. Kales and cabbages also grow with abundance and ease. Pansies and nasturtiums (gorgeous edible flowers) also grow and flower very well in our winter climate.
What about herbs?
Palm Beach County’s winters open the door to successful herb gardens. Some of our favorite and most desired herbs are very challenged to make it through our hot, humid summers but grow extremely well in winter. Some favorites that will only thrive during cooler months are cilantro, tarragon, sage, borage, dill, and lavender.
What about flowers?
If you are speaking of annuals, any and all do well in winter. Some of my favorites just for winter are fuchsia, snapdragons, and violas.
Any suggestions for how to structure a winter garden plot?
Design is so subjective that it’s hard to present a one size fits all. Today, I am very fond of mimicking a French style called a potager or ornamental kitchen garden. It often has some definite lines and balance of formality but flowers (edible and non-edible) and herbs are planted with the vegetables to enhance the garden’s beauty.
What type of soil should be used?
Until you go quite a few miles westward [and] reach the agricultural muck soils of the everglades, our soil is extremely, nutritionally poor and sandy. Generous addition and incorporation of humus, compost, and organic matter is required to grow most plants. I would go as far to say close to a fifty-fifty mix. If you are growing in containers, I would purchase an artificial spoil that contains more than 70-percent organic matter and a slow release fertilizer already in the mix.
Any suggestions for maintaining vegetation that typically isn’t suited for colder weather?
Keep it well watered, mulched, and planted in a protected spot such as adjacent to a building or protected from strong winds. You’re taking a chance in South Florida planting extremely tropical species but you might just have the perfect microclimate and succeed.
Anything else our readers should know?
Try not to do heavy/major pruning after December 1. Pruning often initiates new tender growth that might not be able to withstand the occasional cool spells as well as mature foliage does. Visit and support your smaller, family-owned nurseries for good advice and healthy plant material. We all shop the big retailers but we get our best advice and plant material from the individual attention received from the smaller guys who are the experts with experience.