Iron phosphate baits will save driftwood roses
Answer. Populations of slugs and snails that feed on plants are easily controlled using iron phosphate baits. Many brands of slug control contain this active ingredient. It is considered a safe pesticide to use in landscapes frequented by pets and family members. When applied as directed, under and near plants, including roses, it should not cause any harm to your roses.
s. A beautiful senna bush is thriving in my garden, but its leaves are falling. What can we do to save the plant?
a. Senna bushes, also called butterfly bushes and cassias, put on a dazzling display of yellow blossoms in the fall. Plantings should not lose their leaves, so make sure the soil is moist during dry times. Although the plants appear to be drought tolerant, they drop their leaves when they dry out. Also look for dead or deteriorated areas on the trunks, which may indicate that the shrub has a fungal problem. In this case, try pruning the dead stems back to healthy wood. Eventually, you may need to plant another senna bush in a different location to make it look equally impressive next year.
s. I grow cucumbers and have found the worm depicted on many of the fruits. How do I keep them out of my crops?
a. We all need protein, but not what comes from the organisms found in cucumbers. These fruits, along with squash and watermelon, are favorite foods for pickleworms and watermelon. They start out as eggs laid by small brown butterflies. The eggs hatch into larvae that develop into the worms you found in the cucumbers. If only a few fruits are affected, the worms may be ignored, but when every fruit seems to have some, control is needed. Gardeners can use Thoracid or an insecticide containing spinosad by following label instructions. These naturally derived products are often used by organic gardeners and are considered low toxic to all but caterpillars and other larvae. Either or both are available in the Bonide, Fertilome and Southern Ag lines of insecticides for grub control.
s. The jasmine vine is out of control. When is the best time to prune it back, and by how much?
a. There is still time to do the pruning required for this cold-tolerant vine, but hurry. In general, we don’t want plants to produce a lot of new growth when very cold weather arrives, usually in January or February. If you want to wait to prune, mid to late February is the next best time. The vine can tolerate severe pruning, so cut it back as needed, allowing room for new growth.
s. We would like to add shrubs in front of the house. We are looking for something hardy, easy to grow and without frequent care, like viburnum. What is available?
a. There aren’t many shrubs available to satisfy your landscape desires, but the Sandanqua viburnum shrub, commonly known as hanging viburnum, may work. Most viburnum plants grow very tall and wide, but this one grows to about 6 feet tall and can be kept a few feet wide. The pendant can be maintained with a little care two or three times a year, usually with hand shears. They also thrive in light shade in full sun and can maintain good growth with two or three feedings per year. Another easy-to-maintain landscape mainstay is the dwarf yaupon that grows up to 4 feet tall. It is drought tolerant and can survive in light shade to full sun. Additional shrubs to consider include brilliant jasmine, plumbago and threalis. All can survive on minimal nutrition but grow best in moist soil.
November in the park
s. Squirrels are trimming the limbs of my elm trees. How do I prevent them from damaging trees?
a. A repellent found at local garden centers will likely be helpful. But then, you have to find a way to spray a large tree fairly frequently for a month or two. In fact, it’s probably best to ignore the damage and collect the short stem pieces that fall to the ground for a compost pile. A lot of damage looks bad, but it usually only amounts to light pruning. No one seems to know for sure why squirrels have a bout of chewing at this time of year. They probably enjoy the sugars that trees store in the tender ends of the trunk in preparation for winter. They may also stuff their nests with some tree parts loaded with ash seeds.
s. I would like to plant a row of azaleas along a 20-foot fence. What type of 3- to 5-foot azaleas can I grow and when do they bloom?
a. The prime bloom time for most azaleas is late winter and early spring. Usually, you can count on a good offer at the end of February and early March. Now, here are some things to think about. First, azaleas grow best in acidic soil. Without a pH between 4.5 and 5.5, plants tend to have limited vigor, and the foliage may be on the yellow side. Plants also like a filtered sun location. If it is too shady, the plants produce fewer flowers, and if the plants are in the sun, their leaves will be yellow-green. When conditions are right, any azalea suitable for Central Florida should give good growth and color. When growing conditions are less than ideal, consider one of the South Indian varieties. Some selections in the 4 to 6 foot range include Formosa, George L. Taber, Mrs. J. J. Gerbing, and Southern Charm. Note that azaleas need frequent watering and feeding to be at their best.
Tom McCubbin is an urban horticulturist emeritus with the University of Florida Cooperative Extension Service. Write to him: Orlando Sentinel, PO Box 2833, Orlando, FL. 32802. Email: TomMac1996@aol.com.
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