by Daniel J. Leonard | Jul 3, 2018
Each time I travel to central and south Florida and observe the wonderfully flamboyant tropical flora, I am reminded of the unique and frustrating climatic characteristics of Northwest Florida. Our weather is tropical enough through the summer to sustain virtually everything our friends to the south grow, but winters north of the Big Bend are just cold enough to prevent long-term success with most tropical species. However, the genus that is maybe most synonymous with tropical color, the Hibiscus (it even has its own texting emoji!), contains several species that are hardy through our winters. The best landscape plant of these hardy Hibiscus species is creatively (sarcasm) called Hardy Hibiscus or Giant Rose Mallow (Hibiscus moscheutos) and is an absolute star in the Panhandle, bringing the beauty of the tropics to your yard!
Hibiscus ‘Starry Starry Night’ – Photo courtesy Daniel Leonard
Rose Mallow is a native perennial species that occurs in sunny wetlands across the eastern U.S. This species can grow 7-8’ in height in its natural, unimproved state and possesses the largest flowers of any hardy perennial, some varieties easily eclipse 12” in diameter. Rose Mallows bloom through the heat of our long summers and return reliably each winter unfazed by frost. The flowers also happen to be a favorite of butterflies and hummingbirds and bring beneficial wildlife to the landscape. These characteristics and the trend towards the use of pollinator friendly, low-maintenance native perennials in landscapes quickly made Rose Mallow a jewel for plant breeders and now virtually all major horticultural brands have a line of Hardy Hibiscus available at garden centers, in varying sizes, flower color and leaf color/form. Recent breeding efforts have focused on introducing plants with enormous, richly colored flowers held on compact plants with attractive foliage. The results have yielded two series and three individual cultivars that I consider superior selections and are more than worthy of inclusion in your garden:
- Summerific® Series by Proven Winners. This series is comprised of four robust (up to 5’ in height) cultivars, ‘Cherry Cheesecake’ (bicolor magenta and white flowers), ‘Berry Awesome’ (purplish lavender flowers), ‘Cranberry Crush’ (a red you really have to see to believe), and ‘Perfect Storm’ (notable for its deep purple foliage).
- Luna Series by Monrovia. This series is notable for its ultra-compact (3’ in height or less) size and characteristically large flowers. It is also composed of four cultivars, ‘Luna Red’ (deep red), ‘Luna Blush’ (white, fading to pink near flower margins), ‘Luna Pink Swirl’ (pictured and my favorite, bicolor swirly flowers), and ‘Luna White’ (white with a red center).
Hibiscus ‘Luna Pink Swirl’ – Photo courtesy Daniel Leonard
- ‘Starry Starry Night’ by Walter’s Gardens. (Pictured) This cultivar combines dark purple to black leaves with swirled pale and dark pink flowers. It has performed very well in my landscape and if I could only grow one, this might be it.
- ‘Lord Baltimore.’ The classic, large growing cultivar with bright red flowers that is widely available and easily found. An oldie (introduced in 1955) but a goodie.
- ‘Midnight Marvel’ by Walter’s Gardens. A “hot off the press” new cultivar that is currently difficult to find due to popularity, though some online outlets have them available in small sizes. This one is worth your patience. Sporting deep red blooms on near black foliage, there’s nothing else like it in the landscape.
In addition to being gorgeous plants, Rose Mallows are extremely versatile in the landscape and could not be easier to grow. Because the size varies so greatly (from the diminutive 30” tall ‘Luna’ series to the 8’ tall unimproved species), there really is a place for one in every garden. I like to use the smaller cultivars in large containers to facilitate moving them around where their floral display has the greatest impact or to create a tropical effect where in ground plantings are not an option (pool decks, patios, etc). The larger cultivars make spectacular specimen plantings in perennial and shrub beds and even make a really dense, striking hedge (just know they disappear in the winter). Be sure to give them as much sun as possible, as this will enhance the number of flowers on each plant and darken the foliage on the cultivars with purplish/black leaves. Too little sun will result in fewer flowers and lighter green foliage. As wetland plants, Rose Mallows enjoy regular water, either from rainfall or irrigation; they will let you know when they need it – their large leaves readily wilt under drought stress, somewhat like Hydrangea.
For low-maintenance, native, pollinator friendly, cold-hardy tropical color, you need look no further than Rose Mallow. These perennial shrubs come in all sizes and colors and fit any landscape! Look for the above listed series and cultivars at better garden centers and online retailers and enjoy the oohs and ahhs elicited when people first get a glimpse of Hardy Hibiscus in your landscape! Happy Gardening!
by Daniel J. Leonard | Jun 21, 2018
It’s that time of year. School is out, hurricane season is in, and the mercury is up! Gardens wilt by midday and gardeners retreat into the air conditioning long before then. Unless you have your toes in the water on one of Northwest Florida’s beautiful beaches, it can be a miserable time to be a Floridian, for plants and people! However, despite the relentless heat and blistering sunshine, low-maintenance, eye-catching color can still be had in the landscape. When the calendar flips to June, I turn to my two favorite Florida-Friendly annuals to do the heavy lifting in my landscape: ‘Diamond Frost’ Euphorbia, and the ‘Cora’ Vinca series.
‘Diamond Frost’ Euphorbia – Photo Courtesy Daniel Leonard
A relative newcomer to landscapes, the award winning ‘Diamond Frost’ Euphorbia is an amazing introduction from Proven Winners. The ultimate in tough, ‘Diamond Frost’ does great both as a mounding accent in a container or as a standalone bedding plant in the landscape. Though its individual, teardrop-shaped, white flowers are tiny, the hundreds of them that open each day really pack a floral punch in the landscape! One caveat: if planting in the landscape, I find ‘Diamond Frost’ to be most effective massed in groups of three or more. Due to the daintiness of the flowers, a single plant can get lost among other garden inhabitants. However, when done right, ‘Diamond Frost’ is a proven winner in any landscape!
Mixed container featuring ‘Diamond Frost’ Euphorbia – Photo Courtesy Daniel Leonard
Next, the ‘Cora’ series of Vinca (Catharanthus roseus), also introduced by Proven Winners, is an improvement on an old favorite. Note: This species is also, on occasion, called Periwinkle. However, do not confuse it with the spreading, purple-flowered, perennial groundcover of the same common name! Gardeners in the South have been growing Vincas for years. This species is unbelievably tolerant of harsh conditions, sometimes even seen growing in sidewalk cracks! However, the unimproved species had an Achilles heel: susceptibility to Phytophthora, a devastating fungal rot disease. ‘Cora’ overcomes this issue and is as close to a perfect bedding annual as you’re likely to find. The ‘Cora’ series is composed of cultivars with pinwheel-shaped white, pink and lavender flowers, a color for everyone! The kind (and clever) marketing folks at Proven Winners have even made ‘Cora’ easy to spot on retail nursery benches; just look for the plants in the hot pink containers!
‘Cora’ Vinca
Photo: Andrea Schnapp
Both of the above-described plants are extremely undemanding of gardeners. Once established, little is required in the way of irrigation and fertilization. To ensure success, water daily for the first week after planting, back off to a couple of times per week for the next two weeks or so and then watch ‘Diamond Frost’ and ‘Cora’ thrive with only rainfall for the rest of the summer! Keep in mind, during periods of excessive drought, supplemental watering may be required to keep any plant, even drought tolerant ones, looking their best! To meet the minimal nutrition demands of these plants, I incorporate a quality, slow-release fertilizer (for example, Osmocote, Harrell’s Polyon, or any other similar product) at planting. These products last two or three months in our rainy, hot, humid climate and generally need a second application accordingly for full-season performance. ‘Diamond Frost’ Euphorbia and ‘Cora’ Vinca also require full, blazing sun for maximum floral performance. Don’t be shy about siting them in harsh, sunny places, even a few hours of shade tend to make leggier plants that flower less!
Mixed container with ‘Cora’ Vinca accent
Photo: Andrea Schnapp
When you need low-maintenance, season long color that can beat the heat, look for ‘Diamond Frost’ Euphorbia and the ‘Cora’ series of Vinca at your local nursery! Stay cool out there folks and happy gardening!
by Daniel J. Leonard | May 4, 2018
H. macrophylla ‘Bloomstruck’
Photo courtesy of Andrea Schnapp
Generally, when folks find out what I do for a living, among the first questions asked is “What is your favorite plant?” Being somewhat of a plant nerd, that can be a tough question to answer! However, I usually circle back to the same answer, “Hydrangea”. There are many reasons my fellow gardeners and I love hydrangeas. It’s undeniable that few plants conjure more fond memories of summers gone by or cause more impulse purchasing at nurseries than a hydrangea in full, billowy bloom. Additionally, few specimen shrubs give more floral firepower and ask so little of the gardener in return. My own love affair with hydrangea stems from my first propagation experience, a softwood cutting of Hydrangea macrophylla ‘Nikko Blue’ (taken with the help of someone who knew a lot more about what they were doing than I did) that, seemingly magically, sprouted roots in a makeshift greenhouse, a cypress box with an old, crusty, sliding glass door. Hydrangeas hooked me. However, even with all of those attributes to its name, Hydrangea, as a genus, remains underappreciated and underutilized in modern landscapes. Let’s shed some light on the two primary reasons for gardeners’ failure and frustration with hydrangeas in the landscape and highlight some of the best Hydrangea species and cultivars to look for at the nursery!
First, hydrangea has a reputation as being a high water user. As the name (hydrangea comes from “hydor”, which is Greek for water) might suggest, hydrangeas are indeed water sensitive. However, this does not necessarily mean they require more or less water than other plants, rather they simply betray drought quicker than most other plants. This feature makes hydrangea particularly useful in the landscape as an indicator plant. As a general rule, hydrangeas (particularly those planted in too much sun) wilt in the afternoon heat; this is totally normal. However, if the plants remain wilted the next morning, it is an indicator to the gardener that irrigation is required! If they don’t get irrigation soon after telling you they need it, the plants may begin to decline. Rather than being viewed as a drawback, think of this feature as an early warning system. Name another plant that looks out for us gardeners like that!
The second primary reason people fail with hydrandea is improper site selection. Attempting to grow hydrangea in full sun in Florida leads to less than spectacular results. All species of hydrangeas are most happy when sited to receive at least some afternoon shade, if not filtered shade throughout the entire day. Exposure to blistering afternoon sun is problematic and results in increased wilting from heat stress, increased irrigation requirements and “bleached” flower coloration. Remember, there are fewer frustrating things than growing the right plant in the wrong place!
Now that you know how not to fail with hydrangeas, it’s time to select the proper plant for your property! Three primary species perform noticeably better here than the rest of their kin and deserve the gardener’s consideration in Northwest Florida: H. macrophylla (Bigleaf Hydrangea), H. quercifolia (Oakleaf Hydrangea), and H. paniculata (Panicle Hydrangea).
H. macrophylla
H. macrophylla, the old-fashioned hydrangea everyone’s grandmother grew, is truly one of the standouts in the shady, Southern landscape and commands attention when in flower. Sporting giant “mopheads” of inflorescences in gorgeous hues of blue (or pink, depending on soil pH), H. macrophylla is an extremely low maintenance plant, requiring only periodic irrigation and infrequent fertilizer; H. macrophylla even tolerates salt spray and can be grown on the Gulf Coast! By far, the greatest percentage of questions I receive concerning H. macrophylla involve plants not flowering because of pruning at the wrong time of year. For best flowering results, time pruning of once-blooming traditional cultivars like ‘Nikko Blue’ soon after flowering is finished in late summer. These plants set flower buds on the previous season’s wood; pruning older cultivars in the fall or winter may rejuvenate the plant but will prevent flowering the next year! Fortunately, over the last twenty years, advances in Hydrangea breeding have given gardeners the option of planting remontant cultivars that bloom on current season’s wood. Commonly sold remontant cultivars like ‘Endless Summer’, ‘Penny Mac’, ‘Bloomstruck’, and ‘All Summer Beauty’ have an early summer flower display like the traditional types but then continue to flower periodically throughout the rest of the summer! Even better, they may be pruned at any time without worry of damaging the next season’s flower show!
H. quercifolia (Oakleaf Hydrangea) Photo Courtesty of Andrea Schnapp
Those looking to diversify their hydrangea collection should next look to the native Oakleaf Hydrangea (H. quercifolia). The Oakleaf Hydrangea is a Florida native, growing wild on the steep, shady ravines along the northern end of the Apalachicola River. If the plants never flowered, the Oakleaf would be worth planting; its massive leaves, oak-shaped as the name suggests, can grow up to a foot in length and provide some of the best fall foliage color available to Floridians. However, the real show, as with all hydrangea species, are the flowers. This species flaunts 8”-10” white, panicle shaped flowers that are held elegantly above the coarsely textured foliage. In addition to these features, Oakleaf Hydrangeas couldn’t be easier to grow; obtaining heights up to 10’ and asking very little of the gardener other than adequate irrigation and some shade in the heat of the day! Look for the author’s favorite cultivars: ‘Alice’, ‘Semmes Beauty’, and ‘Snowflake’. Each of these cultivars and selections of the common species H. quercifolia perform very well in Northwest Florida.
H. paniculata ‘Quickfire’
Photo courtesy of Andrea Schnapp.
Finally, the newest hydrangea species introduced to Florida gardens, H. paniculata, has made significant inroads in the landscape industry over the last decade. Primarily grown as the cultivar ‘Limelight’, H. paniculata overcomes some of the weaknesses of the two aforementioned species, namely it tolerates full-sun and persists on much less water, making it a potentially more sustainable plant for many landscapes. This plant, like the remontant H. macrophylla cultivars, blooms on new wood and even seems to enjoy a hard pruning each winter; plants pruned this way seem to be more vigorous the next season and produce larger greenish-white flower panicles than unpruned specimens. Though it is a relative newcomer, H. paniculata, particularly ‘Limelight’, is a worthy addition to any landscape.
As you can see, there is a hydrangea for every yard and no true Southern landscape is complete without a few. When perusing your local garden center this summer, look for the selections and species mentioned above, plant properly, and enjoy the ensuing annual flower show for many years into the future! Who knows, you may be hooked by hydrangeas as I once was!
by Daniel J. Leonard | Feb 2, 2018
It is a common misconception that winter is a time of rest in the landscape, for both plants and people. In the Panhandle, the winter months tend to be rainy and miserable, with wild weather fluctuations in between. These conditions cause folks to think their chores are done until the weather warms up and plants begin to grow again. In reality, winter lays the foundation for the next year of growth! This is because, though most plants are dormant or have at least slowed their growth above ground, their root systems continue to develop through the cold. This “catch-up” time when plants are not growing above ground is the ideal time to plant woody trees and shrubs so they can focus their energy on getting a root system established without having to worry about supporting shoot growth! However, even if you plant at the proper time, several common mistakes can still torpedo your planting efforts. I once worked for a snarky nurseryman who, when new employees would ask how he wanted trees to be planted, would answer, “Green side up, of course.” So, remember to plant green side up and also keep the following in mind when you plant this winter!
Cutting circling roots.
- Digging the right hole. The quickest way to resign a plant to failure before even removing it from the container is to dig a bad hole. In order to facilitate ideal root development and allow the plant to establish as rapidly as possible, the planting hole should be 2-3 times the diameter of the rootball. The easiest way to measure this is to set the plant were you want it and begin digging the hole around it; this step allows you to visualize the size of the hole. Most holes that are “eyeballed” are not wide enough. A little extra digging in the beginning can make a lot of difference later. In addition, the planting hole should be, at minimum, the same depth as the rootball. In a perfect scenario, after planting, the top of the rootball should be a half an inch to an inch higher than the surrounding soil to accommodate for settling of the soil underneath the rootball. This prevents the plant from sitting in a depression that water could pool in, leading to disease issues. It can be hard to believe, but simply digging a proper hole helps ensure plant establishment and enables long-term survival!
- Preventing Circling Roots. Often, plants are constrained in a container that is a little too small for a little too long on the floor of a nursery. When this situation occurs, the roots of the plant do not stop growing once they reach the “wall” of the container, but rather keep going in a circular pattern around the edge of the pot. This is a problem because, if not corrected, the roots will continue this growth pattern once in the ground, eventually strangling the plant. However, this problem is easily corrected by severing the circling roots. This is where gardeners often get squeamish however. It is time to check your plant conscience at the door and know the plant will thank you later! I like to make vertical slices, evenly spaced, around the rootball. These slices should cut about an inch into the rootball to ensure both superficial and unseen circling roots are cut; this somewhat brutal task can be accomplished with a sharp shovel, machete, or even a heavy-duty pair of pruners. At every cut, the previously circling root will branch, creating a nice web of new roots that will serve as anchors for the fledgling plant.
Backfilling Correctly. The single most asked question involving plants trees and shrubs is, “Should I backfill the hole with compost?” The single most common answer I give in return is, “Absolutely not.” Although it seems counterintuitive, it is almost never a good idea to backfill with a soil that is not your native soil. There is a simple reason for this. If a tree were planted in a hole that is backfilled with rich soil and is surrounded by our infertile, native Florida sands, why would it ever want to leave that hole? Turns out, it does not want to leave that easy environment because it has all the nutrients it needs right there, which is a problem. What happens when a drought, hurricane, or other stress event comes calling? The plant will not have a wide-spreading root system for support and will suffer from lack of water or lodging from high winds. By backfilling with your native soil, you encourage the plant’s roots to grow out and seek water and nutrients.
As you can see, there is a little more to planting than “green side up.” But, if you plant at the right time, dig the right hole, prevent circling roots, and backfill with your native soil, you will have set your newly bought tree or shrub up for success and will be able to enjoy it for many years to come! For more information on planting and other horticultural topics, contact your local UF/IFAS Extension office and as always, happy gardening!
by Daniel J. Leonard | Jan 10, 2018
Are you guilty of “Crape Murder”, the dreaded horticultural sin that involves lopping off your beautiful Crape Myrtles fence post high and creating gnarly looking knuckles? No need to raise hands, you know who you are! Despite the cruelness of this act, all is not lost; there is still time to repent and change your ways! The facts of the matter are, if you have made a habit of lopping the tops off your crapes, you are most definitely not alone, you probably thought you were doing the right thing, and it can be corrected.
Improper pruning of crape myrtles. Photo Courtesy – Beth Bolles.
Crape Myrtle (Lagerstroemia spp.) are one of the most beautiful trees Southerners have in their horticultural arsenal. Unsurpassed in both form and flower, it is easy to see why Crape Myrtle is the most widely planted tree in the Southeastern United States. A mature Crape Myrtle properly grown is a remarkable sight, sinewy limbs reaching high in a vase shape supporting lilac-like flowers that come in a rainbow of colors. These qualities make it even more strange that homeowners and landscape professionals alike insist on butchering them every winter.
Before we move on to corrective procedures, let us examine a few of the reasons that crape murder is committed. First, I think peer pressure has a lot to do with it. When one sees every house on the street and all the business landscapes doing things a certain way, one tends to think that is the correct way. Second, there are folks who believe that pruning their crapes back each year creates a superior flower show. In reality, this practice creates an overabundance of succulent, weak, whippy branches (with admittedly larger flowers) that tend to bend over and break after a summer wind or rainstorm and are more prone to pests and disease. In addition, many homeowners over prune their crapes in this way because they planted a cultivar that grows too large for the site. There are dozens of crape myrtle cultivars sold, be mindful to pick one with a mature size and shape that will fit with the scale of the site!
So, now that we know why crape murder is committed, let’s discuss how to remedy it once the atrocity has already occurred.
- If the improper pruning has not been going on very long (a couple of years or less), it may be possible to correct over time without taking drastic measures. If this is the case, select two or three of the young “whippy” canes that are growing up and out and remove the rest. Ideally, the canes you select will be growing away from the center of the plant and not back into the middle of the plant or straight up to facilitate proper branch spacing as the tree continues to grow. The canes you select now will become primary branches in the years to come, so plan and prune carefully. Repeat for each main trunk that has been “murdered”. You will have to keep watch on the cut areas, as they will attempt to regrow as suckers after pruning; simply remove these juvenile shoots until they stop emerging.
Properly pruned crape myrtle. Photo courtesy – North Carolina Cooperative Extension
- If the murder has been going on for more than a year or two, it likely cannot be corrected without a major rejuvenation of the plant. Though it will likely be painful for you emotionally and seemingly run counterintuitive to your instincts, the best method to rejuvenate a disfigured crape is to break out the chainsaw and cut the plant back to the ground! This forces the plant to do one of two things; either grow an outrageous number of new shoots or die. In most cases however, the crape myrtle’s tough constitution permits it to regrow from the stump. The first growing season after performing this procedure, allow the shoots that sprout to grow and do not prune. The winter following the first growing season, remove all except three to five strong, well-spaced shoots and allow these to become the new plant’s main trunks. In all succeeding years, only prune to remove dead wood, crossing branches and branches growing toward the center of the plant.
If you have been guilty of crape murder, it is not too late to change your ways! Follow these steps, get out and enjoy the cool weather, and get to correcting your mistakes while the plants are still dormant! As always, if you have any questions about the topic of this article or any other horticultural topics, please contact your local Extension office and happy gardening!
