Welcome butterflies to your garden, and respect palms, too
The gumbo limbo tree is recognizable by its coppery bark. The tree is salt-,drought-, and wind-tolerant
March 13, 2021
We saw our first zebra longwing, or zebra heliconian (Heliconius charithonia), in the garden last week.
This distinctive butterfly with its long black-and-yellow striped wings was designated Florida’s state butterfly in 1996. Zebra longwings are the only butterflies known to eat both nectar and pollen, which probably accounts for their long lifespan: they can live up to several months, rather than the few weeks of most butterflies. The beautiful white caterpillar with its black spikes arranged in triplicate across the back is especially fun to find.
Zebra longwings are easily attracted to your garden by planting corky stem passionflower (Passiflora suberosa) or maypop (Passiflora incarnata). As the caterpillars feed on the leaves of these plants, they acquire toxins, making them distasteful to predators; they advertise this toxicity through the striking color and patterns of their wings.
The passiflora species bursts with color
Corky stem is Florida’s most common native passionflower and is the preferred host for not only the zebra longwing, but also julias, Gulf fritillaries and variegated fritillaries, so you’ll be getting lots of other butterflies in the bargain. This is a fast grower and is very happy planted at the base of a palm or other tree in full sun to part shade. Once established, it will take off and you’ll have butterflies in no time.
Maypop has a more extravagant flower with an alluring fragrance, but is more difficult to find commercially. Both will make wonderful additions to your gardens and you’ll be guaranteed plenty of butterflies.
Another great native vine for attracting butterflies is coral honeysuckle (Lonicera sempervirens), which is also a favorite of hummingbirds. This is easy to grow in full sun or part shade and produces masses of bright coral-red tubular flowers in spring. Once the big show is over, it continues sporadic blooming through fall and winter.
Native wild allamanda (Pentalinon luteum) is also blooming now, with glorious yellow trumpet-shaped blossoms against deep-green foliage. This loves to climb, so give it a sunny spot near a gate or arbor and watch for the skipper butterflies that crawl down the wide floral neck to get to the nectar.
Allamandas will attract butterflies
Shady palms
I was disappointed to read about efforts underway in Miami to remove palm trees in favor of trees that provide more shade. Palm trees produce plenty of shade and are indispensable along narrow streets and sidewalks where larger trees with wider canopies simply won’t fit. They fill an important niche and shouldn’t be summarily dismissed because their canopies are “too small."
Sabal palms grow on the shore of the Intercostal Waterway
A palm obviously won’t provide as much shade as an oak, but both have great value. In different settings. Florida’s state tree, the sabal or cabbage palm (Sabal palmetto), is slow-growing and long-lived, and when planted densely along a street, will provide valuable shade for an indefinite period of time. There are many photos of 100-year-old sabals in urban areas.
Sabals can be planted with or without their “boots," those interesting extensions left after the fronds fall off. Planting oaks along streets or narrow sidewalks is impractical: the roots will ultimately grow out too far and rip up the sidewalk, and the extensive canopy will have to be regularly pruned to avoid interfering with traffic. Oaks planted in these locales will ultimately have to be removed and the city will be back to ground zero – the palms should have been kept in the first place.
Planting oaks in parks or in larger areas where their roots and canopies have room to spread is ideal. Oaks are incredibly valuable for the number of insect species they support, but sabal palms are no slouches in this department either, producing elegant inflorescences in late spring containing thousands of fragrant creamy white flowers important to bees and other pollinators. The black fruits that follow in fall are an essential food source for wildlife.
A roseate spoonbill wades among the “boots” and fronds of sabal palms
Sabal palms are drought-, salt-, fire- and wind-resistant – withstanding heavy winds better than 97% of other trees. They are often the only trees left standing with any foliage after major hurricanes have decimated the canopies of other trees. Live oaks and other native shade trees are vitally important, but let’s not remove our equally valuable sabal palms without first understanding their inherent value to specific situations.
Over-pruning
While we’re on the subject of palms, I want to mention the routine incidence of over-pruning, which is detrimental to the aesthetic, functionality, and health of the tree. Palms should only have their lower dead fronds removed, never the healthy green ones, as these are the photosynthesizing energy factories of the tree. Sadly, palms are often dramatically scalped, leaving only a few “mohawk” fronds on the top.
Sabal palms, and palms in general, are naturally able to withstand high winds, so the "less is more" adage is best applied in pruning: the “hurricane cut” that some landscapers encourage is totally unnecessary. Sabal palms are self -pruning, meaning they shed their dead fronds automatically. If your palms aren’t self-cleaning, remove only the lower dead fronds; nothing above the 3- or 9 o’clock line should be touched.
And don’t allow your landscapers to use tree spikes to climb the tree — these cause permanent damage to the trunks and leave wounds open for infection and disease. Our beautiful state sabals are essential to maintaining sustainable habitats in urban areas.
A sabal palm grows through a strangler fig tree
Clearing up misunderstandings
Since we’re on the subject of sabal palms, I thought I’d dispel a few misunderstandings about our native strangler fig (Ficus aurea) and banyan tree (Ficus citrifolia), with whom the sabals have an interesting relationship.
A sabal palm hosts a ficus
Figs are the most common flowering plants growing epiphytically on sabal palms, germinating in the boots of the palms after their seeds have been deposited by birds. The seedling fig receives nourishment from its feeder roots in the detritus within the boots while it sends aerial roots down, creeping around the palm trunk or just hanging until they come in contact with the ground. At this point, they root and begin growth as a new tree, in some cases strangling the original host palm after several years.
But as often as not, the trees can coexist, with the palm appearing to grow out of the center of the fig as this much larger tree envelops it. Sabal palms are monocots, so they don’t have a cambium layer that needs to expand with the tree’s growth, as in dicotyledonous trees (such as oaks and maples). Hence, 100-year-old palms can have the same trunk girth as their 20-year-old children.
As the fig grows up around the sabal, the two will compete for light, water and nutrients, but the palms are tough and can usually survive. Strangler figs aren’t picky either about their host trees – sabal palms are easy because of their nourishing boots, but there are plenty of examples of figs growing up around magnolias, oaks and even Australian pines. Next time you see those interesting aerial roots hanging from a banyan or strangler fig, you’ll know where they’re headed and why those trees can get so big.
Butterflies
But let's get back to butterflies. There are plenty of fun native plants in bloom right now, and these may provide some incentive to start that butterfly garden you’ve been thinking about.
Spiderwort (Tradescantia ohiensis) is a wonderful small native with glorious clear-blue flowers. This is a low-care, drought-tolerant plant with long narrow leaves that fits into any garden setting in sun to part shade. It spreads by underground rhizomes, forming neat, attractive clumps.
A starry rosinweed is always a show-stopper
Rudbeckia flowers are great for butterfly gardens
Rudbeckia and coreopsis, both sunny yellow, are great companion plants in a butterfly garden, where they attract hairstreaks and numerous pollinators. Dune sunflower (Helianthus debilis) is another tough, drought-resistant ground cover or accent plant with loads of cheery yellow daisy-like flowers right now in full sun. And starry rosinweed (Silphium asteriscus) is always a show-stopper, with its large heads of brilliant yellow on tall stems above a basal rosette of foliage.
Dune sunflower is drought resistant
Coreopsis flower attracts pollinators to your garden
There’s so much blooming out there and so much diversity – plan a visit to Pan’s Garden at the Preservation Foundation to see some real treasures that you can add to your landscapes. And remember that if you want birds or butterflies, you’re going to have to forego spraying chemicals (pesticides, herbicides, or fungicides). Let the birds and dragonflies eat your insects — they do a great job and they need the nourishment!
-Kim Frisbie
Original article on the Palm Beach Daily News is HERE.