by Matt Lollar | Apr 23, 2018
Recently, an Extension Agent in the Florida Panhandle received a picture of some mushrooms popping up in a client’s garden. These particular mushrooms were in a spot where leftover mushroom compost had been dumped. The compost was previously used to grow oyster mushrooms and the client was hopeful that she had more oyster mushrooms growing in her yard. Unfortunately, the lab results came back stating the mushrooms in question were Armillaria spp.
Armillaria spp. in the garden. Photo Credit: University of Florida/IFAS Extension.
Armillaria spp. cause root rot of trees and shrubs throughout the world. The fungus infects the roots and bases of trees, causing them to rot and eventually die. Some species of Armillaria are primary pathogens that attack and kill plants, but most are opportunistic pathogens that are attracted to unhealthy or stressed plants. Fruiting structures of the fungi can be recognized by the clusters of yellow to brown-colored mushrooms that emerge during wet conditions. However, the mushroom caps sometimes never form and the plant material needs to be inspected more thoroughly to find the disease culprit. Infected plants may have wilted branches, branch dieback, and stunted growth and should be removed and replaced with resistant species.
White mycelial fan under the bark of a root infected with Armillaria tabescens. Photo Credit: Ed Barnard
Management – The best method for controlling Armillaria root rot is with proper plant installation and maintenance. Planting plant material at the proper depth will allow the roots to breathe and reduce the opportunity for the roots to rot. Pruning tools should be sanitized between plant material. Proper irrigation and fertilization will also reduce the risk of plant disease and root rot. Lastly, you can choose to plant a diverse landscape with resistant species.
For more information on Armillaria root rot and a comprehensive list of resistant species, please view the EDIS publication: Armillaria Root Rot
by Matthew Orwat | Apr 17, 2018
Monsieur Tillier – Tea rose from the late 1800s. A good choice where a large, free-flowering shrub is needed – Image Credit Matthew Orwat
Home Gardeners, when they think of roses, their mind inevitably turns to the ‘Knockout’ rose and its offspring. That’s fine, there’s nothing wrong with ‘Knockout’ roses, it makes a great ornamental landscape plant, and it’s easy to propagate.
With all the ‘Knockout’ mania, since the early 2000s, many garden roses, that are well adapted to the Northwest Florida climate, have been left out of the home garden to a large degree.
Several roses, which were grown in Florida commonly in the last hundred years, and recommended by former University of Florida president H. H. Hume in his book “Gardening in the Lower South,” are still grown here today. To obtain these roses gardeners must look to small nurseries scattered throughout central Florida and Alabama, or order them from larger nurseries in Texas where the “Texas A&M Earthkind Rose Program” has taken off.
Below are a few examples of easy to grow roses, that are just as disease resistant as the ‘Knockout,’ but offer more variety in color and form that home gardeners might enjoy as much as or more than ‘Knockout’. They have been grown successfully throughout southern Texas for over 30 years, and at the Washington County Extension Office for the past seven years without spraying fungicides or insecticides. Several of these cultivars were also involved in a 3-year rose trial at the UF/IFAS North Florida Research and Education Center, in Quincy.
One caveat I have regarding these roses is that disease resistance is lessened when irrigated with overhead irrigation. Even the most disease resistant roses will develop issues if leaves are constantly left wet.
Belinda’s Dream makes a moderately sized shrub and produces large flowers, especially in the spring and fall. Image Credit – Matthew Orwat
‘Belinda’s Dream’
‘Belinda’s Dream‘ was bred by Texas A&M Professor Robert Basye in 1988, as a culmination of years of intense breeding and selection for disease resistant landscape and cut flower roses. It makes a 4-5 foot shrub that grows about 3 feet wide. Apple-green foliage clothe its pleasing shrub form. It’s free flowering but not overly vigorous, so it’s easy to keep in bounds. Disease resistance is high, there’s rarely any blackspot of note, under no-spray conditions, and only slight powdery mildew in a few years when conditions are favorable for fungus development.
In cool spring or fall conditions, the clear pink flowers can top six inches in diameter, and contain over 200 petals, but regular hot conditions during the summer usually reduce flower size to four inches. This rose loves to be part of mass plantings, particularly when planted 3 feet apart in a triangular formation. It has a reputation as being moderately easy to propagate.
Rosette Delizy is very colorful and disease resistant. A great addition where a spot of color is needed – Image Credit Matthew Orwat
‘Rosette Delizy’
‘Rosette Delizy‘ is a French Tea rose that was introduced to the U.S. nursery trade in the mid-1920s. Since it was bred before the days of modern fungicides, it sports excellent resistance to disease. It shows no powdery mildew, and only the occasional leaf with blackspot under no-spray conditions.
This is strictly a rose for the coastal south, since it does not like cold temperatures, and cannot thrive north of zone 7b without protection.
Color is striking, opening yellow with petal edges changing to pink as the flowers age. Cooler weather brings out deeper russet and maroon tones. It has a light “tea” fragrance. This mannerly shrub gets 4-5 feet tall and 3-4 feet wide. It requires very light pruning, and can actually be killed from heavy-handed gardeners with shears in hand. Minor flaws noted in this rose are that it is somewhat sparsely foliated, and somewhat difficult to propagate.
Madame Antoine Mari – The perfect buttonhole rose produces flowers with delicate, soft colors perfect for arranging. This rose is a mannerly grower suitable for smaller landscapes. Image Credit Matthew Orwat
‘Madame Antoine Mari’
‘Madame Antione Mari’, a Tea rose, was introduced in 1900 when the buttonhole rose was all the rage. Massive quantities of perfectly formed delicate buds of pink and ivory quickly open into 3 inch flowers that decorate the bush like butterflies fluttering in the wind. Re-bloom is fast. Additional interest in the landscape is created by the deep red color of new foliage.
This makes a mannerly shrub for the small landscape, easily kept at 3-4 feet tall, and 5-6 feet wide by light pruning. Disease resistance is above average in a no-spray garden, with very low blackspot infection rates, and only occasional powdery mildew. This rose has been found to be easily propagated with the author reaching near 100% success rate.
Mrs. B. R. Cant at the Quincy rose trial in 2013.
‘Mrs. B. R. Cant’
No mention of easy to grow roses is complete without the mention of ‘Mrs. B. R. Cant’. In the trials UF/IFAS horticulturists performed at Quincy and Plant City, this variety was rated the best performer. It has been in continuous cultivation since 1901, and is often found at old home sites and gardens in Washington County.
This makes a large garden rose, easily topping 8 feet in height, and just as wide. Deep pink flowers are borne profusely from March to first frost. Disease resistance is outstanding, and it’s easy to propagate. Plants are densely clothed in medium green leaves. This rose is often grown in hedges as a substitute for a fence. One of the best all-around garden roses for the gulf south.
Nursery Availability
I provide presentations at workshops on these roses multiple times a year, throughout the Florida Panhandle. The recurring question I get is, “Where are these roses available locally?” Hopefully this article will inspire some local gardeners to try these easy to grow roses, and others, since these are just a few of the roses available that do very well in North Florida under no spray conditions. If you are interested in more information, contact, Matthew Orwat at UF/IFAS Extension Washington County.
by Ray Bodrey | Apr 9, 2018
Figure: Passalora Needle Blight in Leyland Cypress. Image Credit Ray Bodrey
Leyland cypress (Cupressocyparis leylandii) has been a very popular landscape tree in the U.S. for many decades. It has endearing characteristics, most notably its fast-growing nature and ability to make an appealing boundary around property. However, various diseases have created an overwhelming survival hurdle.
Seiridium or Botryosphaeria cankers (also referred to as dieback) are fungal diseases that can strike Leyland cypress. In general terms, cankers are multiple dark oval lesions that are usually sunken into the bark. The lesions are accompanied by the flow of resin. Discolored branches will be seen first as an indicator. If the fungus finds its way into the body of the trunk, most likely the tree will not survive. With Seiridium canker, girdling of branches and stems is not an issue, however needles will fall off the branches easily. With Botryoshaeria canker, stem girdling will occur, killing the branch, but needles generally will stay on the branch.
Passalora Needle Blight or commonly known as twig blight, caused by the fungus Passalora sequoia, is a major concern in the Southeast. The disease is usually more active in the spring and summer months and affects mostly younger growth. Symptoms of the disease are the browning of needles, followed by needle drop. Disease usually begins on the lower part of the tree and moves up. Sometimes the disease is widespread on one side of the tree only, where sunlight is not able to dry moisture quickly. Ventilation is key when planting these trees as a border hedge. However, the Panhandle environment and climate is very conducive for these pathogens to affect the vulnerable Leyland cypress.
If you have or will plant Leyland cypress, there are some fungicide options to consider as preventive maintenance. It’s important to stress that trees that are already infested, will succumb to the disease regardless of treatment. Fungicides such as Daconil & Mancozeb (Pentathlon) can be used in the spring & fall. Propiconazole is the best fungicide for the warmer, summer months (June through August). Fungicides such as Myclobutanil or Thiophanate-methyl are also commonly used. Always read application directions and pay close attention to the application rate interval.
There are other evergreen options, that have a much higher likelihood of not contracting a fungal disease that can cause terminal results. Native species like the red cedar (Juniperus virginiana) or white cedar (Thuja occidentalis) are great choices. Again, these species are not totally immune to twig blight or other fungal pathogens, but they are hardier and less likely to contract diseases. For more information, please contact your local county extension office.
Supporting information for this article can be found in the following the UF/IFAS EDIS publication, “Cupressocyparis leylandii: Leyland Cypress” by Edward F. Gilman and Dennis G. Watson: http://edis.ifas.ufl.edu/pdffiles/ST/ST67100.pdf & the Clemson Cooperative Extension Publication, “Leyland Cypress Diseases & Insect Pests”: http://www.clemson.edu/extension/hgic/pests/plant_pests/trees/hgic2004.html
UF/IFAS Extension is an Equal Opportunity Institution.
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!
by Sheila Dunning | Dec 14, 2017
Photo by Sydney Park Brown UF/IFAS
Holly has been considered sacred in some cultures because it remained green and strong with brightly colored red berries no matter how harsh the winter, even when most other plants would wilt and die. According to Druid lore, hanging the plant in homes would bring good luck and protection.
Later, Christians adopted the holly tradition from Druid practices and developed symbolism to reflect Christian beliefs. Today, the red berries are said to represent the blood that Jesus shed on the cross when he was crucified. Additionally, the pointed leaves of the holly symbolize the crown of thorns Jesus wore on his head.
Several holly species are native to Florida. Many more are cultivated varieties commonly used as landscape plants. Hollies (Ilex spp.) are generally low maintenance plants that come in a diversity of sizes, forms and textures, ranging from large trees to dwarf shrubs.
The berries provide a valuable winter food source for migratory birds; however, the berries only form on female plants. Hollies are dioecious plants, with male and female flowers on separate plants. Both male and female hollies produce small white blooms in the spring. Bees are the primary pollinators, carrying pollen from the male hollies 1.5 to 2 miles, so it is not necessary to have a male plant in the same landscape.
Several male hollies are grown for their compact formal shape and interesting new foliage color. Dwarf Yaupon Hollies (Ilex vomitoria ‘Shillings’ and ‘Bordeaux’) form symmetrical spheres without extensive pruning. ‘Bordeaux’ Yaupon has maroon-colored new growth. Neither cultivar has berries.
Hollies prefer to grow in partial shade but will do well in full sun if provided adequate irrigation. Most species prefer well-drained, slightly acidic soils. However, Dahoon holly (Ilex cassine) and Gallberry (Ilex glabra) naturally occur in wetland areas and can be planted on wetter sites.
For a more comprehensive list of holly varieties and their individual growth habits refer to ENH42 Hollies at a Glance: http://edis.ifas.ufl.edu/mg021
by Daniel J. Leonard | Aug 11, 2017
Growing in containers can be one of the most versatile ways to add color, texture and mobility to the landscape. However, gardeners generally reach for finicky annuals to fill their pots with pizzazz. The problem with this strategy is that most annuals and perennials need to be watered constantly, fertilized regularly, and changed out with the seasons. That sounds like a little bang for a whole lot of buck! I and most of the real plant people I know fall squarely in the school of lazy gardening and believe there is an easier, less intensive, and ultimately less expensive way to get the same result. This can be accomplished by thinking outside the box and using an alternative class of plants that can fit the same bill of providing color and texture in pots without the headaches and have been sitting on the shelves right in front of us the whole time, the shrubs.
It is beyond me why shrubs aren’t used as container plants more often. Maybe the reason for the lack of use is pure perception; after all, no one with any sense would plant a giant, coarse green meatball or an enormous antebellum azalea in a decorative pot on their front walk. Recent innovations by plant breeders have left this argument moot though as new introductions of old species have revived interest in the entire group. Many of the best of these new cultivars sport traits perfect for container culture (dwarf growth habit, increased flowering, and interesting texture and form) while preserving the ironclad, undemanding nature of their parent plants. The following are a few of my favorite new shrub introductions for container growing!
- ‘Purple Pixie’ Loropetalum
Purple Pixie loropetalum is a low-growing shrub that can spill beautifully out of a container. (Photo by MSU Extension Service/Gary Bachman)
If interesting architecture is what you require in a plant, ‘Purple Pixie’ must be on display in your yard. This dwarf cultivar of the wildly overused purple shrub Loropetalum chinense has taken the horticultural world by storm. The unique combination of true purplish foliage that only greens slightly in the hottest summer sun, ribbon-like pink spring flowers, and a graceful weeping habit make ‘Purple Pixie’ a winner. Give this plant a medium sized container (at least 12” in diameter), water when the soil begins to dry, fertilize infrequently with a slow-release formulation, site in full sun to partial shade, and enjoy for many seasons to come.
This is definitely not your granddaddy’s Ligustrum. Gone are the rampant growth, sickly sweet smelling flowers, and the aggressive nature of ‘Sunshine’s’ parent Chinese Privet (Ligustrum sinense). ‘Sunshine’ is a sterile cultivar with dwarf characteristics (growing 4-5’ with infrequent light pruning), vivid yellow-chartreuse foliage, and most importantly, no flowers. All ‘Sunshine’ asks of us is plenty of sun, occasional fertilizer and a light haircut once or twice a season! Use this plant to frame a dark flowerbed or in a container as a companion to the previous plant, ‘Purple Pixie’ Loropetalum for an extremely striking combination!
‘Sunshine’ Ligustrum. Photo courtesy of JC Raulston Arboretum.
A new take on a landscape standard, ‘Baby Gem’ is an exceptionally compact and slow growing cultivar of Buxus microphylla var japonica. All the same features gardeners love about traditional “full-size” boxwoods remains (tight, formal growth habit, ability to prune into many different shapes and ironclad constitution) but with ‘Baby Gem’ are delivered in a perfect package for a pot. This little “gem” of a plant is perfect for use in a smallish container to frame a formal landscape or to give a sense of order to an informal container garden or border!
So if you’re ready to stop replacing all of your potted plants each and every season, reach for one of these shrubs the next time you are at a garden center. You’ll likely be rewarded with compliments on your creativity, four season interest from the plants themselves, and more time to enjoy being in your garden instead of laboring in it! As always, if you have any questions about this or any other horticultural topics please contact your local UF/IFAS Extension office! Happy Gardening!
Photo by Sydney Park Brown UF/IFAS
