by Les Harrison | Jan 20, 2016
North Florida’s gardeners are facing a new set of challenges dealing with the effects of cold weather. However, a little planning and creativity can make plant protection in the landscape a relatively simple process.
Covering plants to protect from frost. UF/IFAS Photo: Sally Lanigan.
Many homeowners and landscape managers want to know when plants will need protection. The point of freezing is a good rule of thumb for most temperate zone plants.
It is worth noting there is a difference in the terms used for cold weather conditions. Frost, freeze and hard freeze all describe different circumstances.
- Frost is when water vapour freezes on surfaces. It usually happens on clear nights with still air and can happen when reported air temperatures are above freezing.
- Freezing is when cold air moves in and causes temperatures to drop below 32 degrees Fahrenheit. This condition commonly involves low humidity and wind, making drying out a big problem for plants.
- A hard freeze is when temperatures dip below 28 degrees Fahrenheit. Some tropical plants will survive a few degrees below freezing for very short periods, but extended periods of freezing or heavy frost may require lights or other heat used safely in combination with covering the plant.
Some plants can be moved indoors for the holidays and incorporated into the interior décor, rather than cramming them last-minute into a chaotic bundle when a freeze looms.
Get prepared by identifying old sheets, blankets and drop cloths which can be used as covers for tender or tropical zone plants which must remain outside. Test potential covers beforehand to assure all plants will be thoroughly covered.
It is best if the covers enclose the plant entirely without crushing it. Heavy blankets are great insulation, but only a good idea on the sturdiest of plants.
A tomato cage or other support structure can be used to keep the weight off the plant. Covers also need to be secured at the ground with pins or weights to assure cold air does not enter from below and collect under the cover.
Finally, keep storage bins handy and remove the covers in the daytime if temperatures are above 55 degrees Fahrenheit.
Monitor weather reports and react accordingly so tender and tropical plants see spring 2016.
by Beth Bolles | Dec 4, 2015
A visit to a nursery and homeowners will see so many new selections of plants for the landscape. Some of these plants are new plant developments and may include plants we could not previously grow in Florida’s heat and humidity. One new plant series is the Southgate® Rhododendrons.
Anyone from more northern areas of the South is very familiar with the rhododendrons that offer showy spring blooms. Those particular rhododendrons just don’t make it in our Florida climate.
The Southgate® series from Louisiana were developed to be more tolerant of our weather conditions. Homeowners must still consider plant placement very carefully since these plants have some specific requirements even in Florida. Plants will do best in shade or filtered shade, especially in the afternoon. They do like an acid soil amended with compost and areas that are well drained. Homeowners will need to supply water during the growing season to maintain a uniform soil moisture.
Rhododendron foliage with buds.
Consider trying one of these newer rhodendrons if your landscape has a suitable spot and you will definitely enjoy a bright spot of color come spring.
Special Note: If you have animals or children be cautious since all plant parts are toxic if ingested.
by Sheila Dunning | Nov 18, 2015
Camellia sasanqua ‘Kanjiro’ at the South Carolina Botanical Garden
Camellia sasanquas begin blooming this month. Their three-inch diameter blossoms of pink, white, rose or red displayed over glossy, dark green foliage will come into their full glory in November. This robust and stylish aristocrat of the garden is often passed by in favor of its familiar cousin, Camellia japonica. While it’s true that the “japonicas” have larger flowers, Camellia sasanqua has just as many endearing attributes. Like the japonicas, sasanquas have been selected and hybridized into dozens of forms that vary immensely in flower color, size and shape. With a variety of growth habits from dwarf and spreading to narrow and upright, their ability to thrive in part sun or shade, sasanquas are one of the most versatile landscape plants.
Sasanquas bear profusions of flowers in fall and early winter depending on cultivar and location. In general they blossom before Camellia japonica. Sasanquas have mature heights that range from 4-15 ft. The taller cultivars are typically trimmed up as small trees. Other cultivars remain shrubby and limited in height. Their small foliage makes them suitable subjects for formal pruning, although they are quite attractive when allowed to grow naturally. Several sasanqua varieties are ideal for creating dramatic espaliers when trained on fences and walls. Like other cool weather bloomers, sasanquas bloom over a much longer period than most spring and summer plants with buds opening over a three-month period. The blossoms shatter easily and create colorful carpets of petals on the ground, adding to their garden impact. Even when not in bloom the sasanquas make a statement with their beautifully glossy, rich green leaves that excel at providing backdrops for garden neighbors.
Camellia ‘Vernalis Yuletide’ at the South Carolina Botanical Garden
Camellia sasanqua ‘Shishi Gashira’ at the South Carolina Botanical Garden
Sasanqua camellias are native to China and Japan. They prefer rich organic acid soils (the same as azaleas and gardenias). Provide plants with organic mulch such as leaf litter or shredded bark. Broken shade is preferred but sasanquas will tolerate more sun if watered well. Consistent watering is important to continuous blooming. If the experience drought conditions the buds will dry and fall without opening.
Select sasanqua varieties based on what you want them to do in your garden. ‘Shishi-Gashira’ is a dwarf, low spreading plant that is suited well for foundation plants and container specimens. Other compact varieties include the more upright ‘Yuletide’ whose fiery red blossoms are accented with bright yellow stamens and the double rose ‘Bonanza’ which begins flowering in September with flowers that rival the japonica varieties in size and form. If you need larger and faster growing plants for hedges, screens or small specimen tree, consider the white ‘Snow on the Mountain’, double pink ‘Pink Snow’ or pale, shell pink ‘Jean May’. ‘Kanjiro’ and ‘Daydream’ are vigorous upright pink varieties whose single flowers are fragrant.
by Matthew Orwat | Nov 5, 2015
Waxmyrtle. Image Credit UF / IFAS Solutions
Myrica cerifera Southern Waxmyrtle, Bayberry is a large shrub to small tree that is now native to much of Florida and much of the Southeastern United States. It was introduced to Europeans in the 1700s and is considered native by many botanical authorities. Sources disagree to the validity of its native status. It is usually found as an understory plant in lightly forested areas, swamps, brackish areas, as well as around old home sites.
It was planted widely in the 18th,19th and early 20th century as a plant for medicinal and industrial purposes. Four pounds of its berries will yield one pound of wax for candle making. When processed, this wax was also used in surgeon’s soap, shaving lather, and sealing wax. Fermented leaves were used to produce a substance which was said to treat fever, stomach aches, and headaches.
Southern Waxmyrtle can reach up to 25 feet but is best maintained as a 10-20 foot multi-trunked shrub or small tree. It can also be trained as a smaller hedge and several dwarf form exist. Landscapes are enhanced by the shrubs’ olive green foliage, leaf aroma, open, rounded form and waxy blue-green berries. Wildlife enjoy the berries as a food source as well. They can provide dappled shade for outdoor entertainment spaces or front entrances.
Waxmyrtle Leaves. Image Credit Brent Sellers – UF / IFAS Extension
Another benefit of Waxmyrtle is that it can be used in tough-to-landscape roadside and coastal areas since it is both pollution and salt tolerant and will cease to require irrigation once it is established. ‘Pumila’ is a dwarf cultivar suitable to small spaces.
Waxmyrtle is susceptible to few pests and diseases but can occasionally be attacked by webworms, mites and caterpillars. These can be controlled by pruning out of infested areas, forceful applications of water or Bt (Bacillus thuringiensis for caterpillar). It is also occasionally susceptible to canker on old branches and Fusarium wilt in central and south Florida. It is also considered a weed in pasture situations.
References:
by Matthew Orwat | Sep 9, 2015
Azaleas pruned late in the fall will have little or no bloom in the spring. Image Credit: Matthew Orwat
As fall approaches, our spring blooming shrubs such as gardenia, spirea and azalea begin to look unkempt and overgrown. That means it is time to give them a severe pruning to get them ready for winter, right? Not so fast, take a minute to understand the growth habit of each species before diving in with the pruning shears.
Azalea:
Many do not understand that annual spring azalea bloom could be sacrificed completely by pruning spring blooming azaleas at the wrong time.
Pruning traditional azaleas in the fall will result in a loss of spring bloom the following year because most bloom on previous years’ wood. This means that they flower on growth put on throughout the previous growing season. If a gardener removes the previous season’s new growth, they are removing the blooms as well.
So, when is the proper time to prune azaleas? The ideal time to prune is directly after the spring bloom. This will give the plant enough time to generate abundant new growth, thus maximizing bloom next spring.
Even the developers of the Encore Azalea, a new repeat blooming type, recommend pruning as soon after the spring bloom as possible to maximize bloom set for the following year.
For more information on pruning azaleas or on general azalea culture, please read the UF / IFAS publication Azaleas at a Glance or check out the Pruning Azalea page on Gardening in a Minute.
Gardenia:
Gardenia, Image Credit Dan Culbert.
Gardenias don’t need much pruning except to remove any dead or non-productive wood, to help them remain bushy, and to remain the same size as other plants in the landscape. Choose a cultivar that will mimic the size of other shrubs, not one too large for the area. Pruning should be done as soon after the summer bloom as possible. Pruning after the beginning of fall will reduce the next year’s bloom production. Know your cultivar. Some cultivars of gardenia flower on new wood as well as old, while some flower on old wood only.
Spiraea:
Regarding spiraea, prune after the bloom as needed. The closer to the late summer or autumn, the greater negative effect pruning will have on bloom quality since spirea set their bloom in early autumn.
I hope this article prevented a few pruning disasters as well as started a thinking process for the act of pruning your landscape plants.
by Larry Williams | Aug 3, 2015
Damage caused by azalea lace bug. Photo credit: James Castner, UF/IFAS
When azaleas are in a garden, azalea lace bugs are sure to follow. The good news is these insects, that discolor the leaves of azaleas, can be controlled.
Lace bugs live on the underside of leaves and damage their hosts by piercing leaves with their straw-like mouthparts and removing the plant’s juices. Infested leaves have tiny yellow spots on the top surface and are discolored with dark, varnish-like excrement and old insect parts on the underside. Azalea plants begin to look unhealthy as insect numbers increase through spring and summer.
Azalea lace bugs spend winter as eggs on the underside of azalea leaves. They hatch in early to mid-March and then begin to feed and develop into adults.
Lace bugs complete their first generation by late April. They increase in number throughout the remainder of spring, summer and fall. These insects can complete three to five generations in a single growing season. In late September adult lace bugs, in their final generation of the season, lay eggs that will carry the population through winter.
The key to easily controlling azalea lace bugs is to properly time control efforts.
Inspect plants in early spring to see if insects are present. Look for leaves that are whitish to yellow on the top surface (they may be mottled in appearance) and have small, dark, varnish-like spots on the undersides. If leave damage is heavy continue to check plants every week for small lace bugs, which should begin to be visible in late March through April.
Early to mid spring is the best time to control the first generation of the bugs. Proper insecticide application timing will reduce need for further sprays during the rest of the growing season.
Insecticidal soap, horticultural oil, neem oil and most synthetic insecticides provide good control of lace bugs on azaleas. When using these types of chemicals, make sure to spray the backs of the leaves.
Azalea leaf with lace bugs. Photo Credit: James Castner, UF/IFAS
Systemic insecticides available for use against lace bugs include dinotefuran (Safari), imidacloprid (Bayer Advanced Tree & Shrub Insect Control, Merit) and acephate (Lilly Miller Ready-to-Use Systemic, Orthene). When properly applied, one application may provide season long control.
When using any chemical treatment on plants, it’s best to apply the product during early morning or late evening under cooler temperatures but never during the heat of the day or when the plant is in full sun. And always follow instructions on the pesticide label concerning mixing, application and safety precautions.
