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Redbud tree flowers are one of the first signs of Spring

by Theresa Friday.

The promise of spring is upon us.  Redbud trees, with their purple blooms, are an excellent indicator of warmer days ahead.  The redbuds are just beginning to bloom along the Gulf Coast.

Redbuds are small trees in the genus, Cercis.  Trees in this genus are sometimes called Judas trees.  According to myth, Judas hung himself on the related Judas-tree (Cercis siliquastrum) of western Asia and southern Europe, after which the white flowers turned red with shame or blood.

Eastern redbud (Cercis canadensis) is a moderate to rapid-grower when young, reaching a height of 20 to 30 feet. It has an irregular growth habit when young but forms a graceful flat-topped vase-shape as it gets older. The tree usually branches low on the trunk, and if left intact forms a graceful multi-trunked habit.

Redbuds usually bloom in late February or March. Small, pinkish purple pea-like flowers are produced in unbelievable profusion along the branches, and sometimes on the trunk, before the leaves appear. This habit of blooming before the leaves grow out is fairly common among the spring-flowering trees and adds to the impact of the flowers.

The leaves are 3 to 4 inches across and heart-shaped. Leaves are a reddish purple when they open, changing to a dark green in summer. Fall color is usually a poor yellow.

Redbud is a member of the bean and pea family, and you would certainly know that from the fruits. Its seeds are enclosed in a bean pod.  The seed pod is a flat, reddish-brown pod that ripens in the fall.  Eastern redbud seeds or pods are eaten by quail, other birds and deer.  Birds will open pods on the tree to get at the seeds.

Eastern redbuds grow well in some shade in Florida. Best growth occurs in a light, rich, moist soil but Eastern redbud adapts well to a variety of soil including sandy or alkaline. Planting sites for redbud should be in an area that provides part shade in a well-drained soil. Ideally, they tend to grow best as a small under-story tree that receives late afternoon shade. They tend to be happier in the summer time with that extra shading. The Eastern redbud tends to be susceptible to drought stress and sun scald in our hot summers. Eastern redbuds often show marginal leaf burn in the summer time, due to the extreme heat intensity in our area.

The ideal time to select and plant your redbud tree is late winter or early spring.  Select trees that are flowering so that you can chose the true color that you desire. There are several redbud varieties to consider planting in your landscape. They include Mexican redbud, 'Forest Pansy' or the white redbud. These trees all have their own unique and unusual characteristics.

'Forest Pansy' redbud, or red-leaf redbud, is a variety that is a moderate grower to about 20 feet. The main characteristics include red twigs and beautiful, new shimmering, purple/red leaves, which fade to purple-green during the summer.

When caring for your redbud, remember that the bark is thin and easily damaged from mechanical impact.  In addition, this tree is a poor compartmentalizer of decay.  It's best to ring the tree with mulch to keep the lawn mower or string trimmer from wounding the tree.

Eastern redbud is an attractive specimen, and is especially nice in naturalized settings.  Unfortunately, they are short lived.  They often have a functional life of 10 to 20 years in urban landscapes due to a combination of urban stresses, diseases, and pests.

Spread the word, not the weeds

by Theresa Friday

The 10th Annual National Invasive Weeds Awareness Week is February 22-27, 2009.  This week long awareness campaign is intended to focus national attention on the impacts caused by invasive plant species.

Throughout both urban and rural areas, invasive, non-native plants pose numerous threats to the Florida landscape, especially on public lands such as parks and state natural areas. Invasive plant species overrun a variety of habitats, displace native plant populations, disrupt plant/animal associations, deprive wildlife of needed food sources, significantly reduce plant and wildlife diversity, jeopardize rare and endangered plants and animals, support nonnative pathogens and pests, and can alter ecosystem processes such as fire frequency/intensity, water and nutrient availability, soil chemistry and erosion. In addition, invasive plant species have a significant negative impact on agriculture and forestry.

Across the nation, the most significant invasive weeds are spreading at approximately 15% per year. This rate of spread will result in a doubling of infested acres in less than five years. According to a recent Cornell University report, the economic impact of invasive plants and weeds in the U.S. is estimated at $34.7 billion annually.

Education is the key in the fight against invasive plants. We must educate citizens at the local level so they understand the impacts invasive plants have on our native ecosystems, even the impacts to our economy. Throughout  Invasive Weed Awareness Week, take some time to look around and see which invasive plants are growing in your area.

We encourage you to learn how to identify these Florida invasive plants so that you can help stop their spread:

Chinese tallow tree: The Chinese tallow, a.k.a. popcorn tree, was introduced from China in the early 1900s and has since invaded most of the southeastern states. It is a small tree whose seeds are widely dispersed by birds and water runoff. The tree's attractive, light green, heart-shaped leaves that yield bright yellow and red fall colors have made it a popular ornamental. However, this tree is threatening to become the prominent component of marshes, river margins, and dry uplands within its expanding range. Further planting of this tree is prohibited by the Florida Department of Agriculture and Consumer Services and it is listed as a noxious weed by the U.S. Department of Agriculture and the Exotic Pest Plant Council.

Hydrilla: Hydrilla spreads when fragments are transported from one water body to another, usually by boats and their trailers. It grows quickly to form dense mats that shade out and replace native plants.

Cogongrass: This is a perennial grass that grows 3 to 10 feet tall and forms dense monocultures. Cogongrass is extremely aggressive and often grows so thick it prevents other plants from growing. The rhizomes can grow 4 feet deep into the ground which makes this plant very difficult to control.

Air Potato:  Air potato is a vine that produces 'potatoes in the air'. This invasive vine from Africa was introduced into Florida in 1905.  Aside from kudzu, it is the most aggressive invasive vine in Florida. It quickly grows to 60-70 feet in length, high enough to overtop and shade out native trees. The air potato is a member of the yam family and produces many aerial tubers (potato-like growths), which eventually fall off and grow into new plants.

Japanese Climbing Fern: Japanese climbing fern can grow in sun or shade, damp, disturbed or undisturbed areas. It can grow so dense that it forms a living 'wall', leading to the elimination of seedlings and other native vegetation. Japanese climbing fern was added to the Florida Noxious Weed List in 1999. It is a major problem in pine plantations, causing contamination and harvesting problems for the pine straw industry.

For more information on how to properly identify and remove non-native, invasive plants, contact your local Extension Office or visit our website at http://extension.ifas.ufl.edu/environment/invasive_species.html.

2009 winning roses announced

by Thresa Friday

Each year, the All-American Rose Selections (AARS) organization picks new and exceptional roses for the landscape.  The 2009 winning roses are Carefree Spirit™, Pink Promise, and Cinco de Mayo™.

AARS is a nonprofit association of rose growers and introducers dedicated to bringing exceptional, easy-to-grow roses to gardeners across the county. AARS operates a rigorous plant trial program via a network of more than 20 official test gardens throughout the country and representing all climate zones. AARS strives to identify roses that are easy to grow, and evaluates plants on more than 15 qualities, including disease resistance, vigor and fragrance.

For the first time, one of this year's winners is a shrub rose that was grown without any fungicide sprays.  Carefree Spirit is the first and only landscape shrub to date to endure this real-world testing and prevail as a winner. It is a mounding rose that produces deep red blossoms with white twinkles in their eyes. The blooms finish pink as they bask in the sun.

Carefree Spirit amplifies the disease resistance associated with its Carefree lineage, with more than 10 years of hybridization improvement. Much like its parent rose, Carefree Delight, which was an All-America Rose Selections winner in 1996, the petals are beautifully set among abundant glossy, dark green foliage. Surpassing its parent, this rose has better disease resistance, blooming power and will perform well in any area of the country.

Pink Promise is a graceful bloomer with long stems for cutting.  Most impressively, the National Breast Cancer Foundation selected this rose to officially represent a continual blooming promise of compassion and awareness. For every Pink Promise plant purchased, a percentage of the sales will be donated to the National Breast Cancer Foundation to help extend women's lives through education and early detection. This hybrid tea's beauty is enhanced by the contrast of its large pink blossoms set against lush dark green foliage. Along with its stunning appearance, Pink Promise has good disease resistance, and flourishes even in cooler climates. A highly fragrant rose, Pink Promise fills any room with a deliciously fruity scent.

Cinco de Mayo brings a carnival of flowers to every garden. Mysteriously colored, it's an indescribable blending of smoked lavender and rusty red-orange. This festive rose may be impossible to describe but you'll love the endless bounty of multi-colored clusters sitting amongst clean, glossy green foliage and dark red new growth.  The flowers, which hold well and are fast to repeat, radiate the smell of fresh-cut golden apples.  As an AARS Winner, this floribunda has fantastic disease resistance and has performed exceptionally well across the country with little-to-no care. As the offspring of the 2006 AARS award-winning Julia Child rose, Cinco de Mayo enlivens any garden.

All of these roses were evaluated in 2008 for landscape performance and blackspot susceptibility at the ornamental and turfgrass research facility located at the LSU AgCenter's Burden Center in Baton Rouge.

According to LSU AgCenter horticulturist Dr. Allen Owings, "Cinco de Mayo and Carefree Spirit were very impressive, and Pink Promise shows good potential as a hybrid tea rose. Under a "no-fungicide" spray regimen, these roses more than held their own in the war on blackspot last year."

January through the spring is a great time for planting roses.

Stop the improper pruning of crape myrtles

by Theresa Friday

A hideous crime is being committed in many landscapes-crape myrtles are being butchered.  It happens this time every year when people improperly prune these beautiful plants.  Many horticulturists call it "crape murder."

The crape myrtle (Lagerstroemia indica) is one of the most beautiful and popular flowering trees in Florida. Often called "the lilac of the South," this plant is tough, adaptable and showy. Its blooms are large and long-lasting and the tree has great fall color and attractive bark.

The practice of chopping off the tops of crape myrtles has become very commonplace. Many people believe that it is required to promote flowering, some prune because the plant is too large for the space provided, while others see their neighbors doing it and feel the need to follow suit. There may be some instances in which heavy pruning is necessary, but typically light pruning is all that is needed.

Unfortunately, many homeowners and landscape professionals prune crape myrtle trees too severely. Topping, commonly called buck horning or dehorning, involves cutting stems back at an arbitrarily chosen height rather than pruning back to a bud, side branch, or main stem. Topping trees is harmful in many ways and regarded as an unacceptable practice by trained horticulturists and arborists.  It can be very damaging and disfiguring to the tree.

Topping causes profuse growth at the site of the pruning, basal sprouting, and increases susceptibility to disease and insects. It encourages new growth that is too dense to allow air movement and light to reach the inner branches. Large, ugly "knobs" appear where trees have been trimmed repeatedly, and the topped tree has an unsightly appearance until new growth appears.

Although topping may result in larger blooms, those flowers will grow on thinner, weaker branches that will droop, especially after a heavy rain, and may even break. Topping may also shorten the life of your trees.

To properly prune crape myrtles, use the following techniques.

• Remove suckers from the bottom of the plant. 
• Remove crossed, damaged, or diseased branches. For crossed branches, remove the weaker of the two limbs that are crossing or rubbing. 
• Prune the tips of the branches to remove old flowers. If old blooms are removed, a second blooming may occur. 
• Thin out small twiggy growth to allow air to better circulate in the canopy.

Crape myrtle should be a low-maintenance plant.  The best way to ensure this is to choose the cultivar that best suits your landscape needs before planting. There are many new cultivars in different sizes and colors. The dwarf (3 to 6 feet) and semi-dwarf (7 to 15 feet) selections now available make it easy to choose the right size plant for a certain space.

There's no telling how many thousands of dollars are wasted on incorrect pruning of crape myrtles. To be quite honest an unpruned crape myrtle is almost always superior in appearance to a "professionally" pruned one. Some things in nature are hard to improve on.

Spread the word among your friends and neighbors and eliminate crape murder. Use proper pruning techniques on your own trees, or ask your yard maintenance professionals about their pruning techniques. Remember to choose the appropriate size plant for the correct site, and prune very sparingly for beautiful crape myrtles in your yard.