The Plant Doctor: Thryallis shrubs can serve as an accent shrub or an informal hedge
Question: My eight-year-old seedling avocado tree is twelve feet tall but has not bloomed. Will I ever get fruit?
Answer: More patience is needed with this tree. Eight years is a long time to wait for your first blooms and fruit but not abnormal with seedling trees. Your tree is big enough but probably not mature enough. Also, any cold damage during winter keeps the tree in a more juvenile state and adds to the years before fruiting. Keep up the good care which includes three fertilizer applications a year and moist soil. Seedling trees do eventually bear fruit similar to the one you enjoyed, but the wait may be agonizing.
Q. I am seeing a yellow flowering shrub used as a hedge and have attached a picture. Do you know the name of this plant and how well it grows in Central Florida?
A. Enjoy colorful yellow blooms spring through fall from thryallis shrubs, also sometimes called rain of gold. Plant as specimens to serve as an accent shrub or row out a number to create an informal hedge. While the plants can be sheared, they are best left to grow naturally and hand-pruned as needed. The shrubs can grow to eight feet tall and almost as wide. One problem with thryallis is the stems are very brittle. Plant away from landscape activities that may affect the limbs to prevent breakage. Thryallis is sensitive to severe cold but usually grows back from lower stems. Sometimes the cold is a blessing and does the needed pruning we are often too timid to do.
Q. There is a foul-smelling vine growing among our shrubs that some say is the skunk vine. How is it best eliminated?
A. Better get this invasive vine under control as soon as possible because it is sneaky. Skunk vines usually start from seeds produced from somewhat attractive little flowers. When the plants start growing, they send out runners at or slightly below ground level. These runners snake along the soil line and send up shoots to climb any plant they encounter. Just tug at some of the vining portions, and it becomes obvious why these are named skunk vines. Getting control of skunk vine is not easy, so remove any growths as noted. Pulling and cutting the vigorous growths to remove them from plants is your first control technique. Then where possible, treat new shoots with a brush killer found at local garden centers. Most can be used on vines near other plants, but only treat what you want to control following label instructions. Persistent removal of skunk vine is the only way to keep it under control at this time.
Q. All of a sudden, my cucumbers are developing holes with ooze. When we cut them open, we find a worm. What should we do?
A. Melon and pickle worms seem a bit late arriving this year, but they are now present and feeding on cucumbers, squash and melons. What you notice is the work of a larva stage of a small brown adult moth. The moths lay eggs on the cucumber plants and the larvae bore into the fruits producing the excreta that looks like an ooze. Our dry spring may have slowed the arrival of the moths, but now, at the start of the rainy season, they are back and heavy feeders. Control melon and pickle worms with a natural insecticide that could include Thuricide or a spinosad-containing product. Both are generally found at independent garden centers and are effective when you follow label instructions. These products also give control of caterpillars feeding on tomato and corn plantings.
The Plant Doctor: Acidic soil will keep hydrangeas blue
Q. Our grapefruit tree is dropping its young fruit. It is about five years old, and I have never seen this happen before. Any ideas?
A. You may not like it, but your tree has a good idea — it is regulating what it can support. This grapefruit tree is young, and it is not often good crops are produced within the first five to seven years. All citrus can experience three fruit drops or thinning within a year. Many very immature fruit drop during or shortly after flowering as they are being set on the limbs. The second drop is often called the June fruit drop, as it occurs at this time of the year. The third drop is around September as the tree matures the crop. Sometimes the fruit loss is excessive, but the trees will thin out what cannot be supported by stored foods or due to growing conditions.
Q. I was given a large older orchid plant in a hanging basket. It has lots of dry shoots that look dead but many new green ones too. What should I do?
A. You have been given a great gift that only needs a little care. Do prune off dead or declining portions but keep the good green stems and leaves. This may also be a good time to repot and even divide the orchid. You may want to take your plant to a University of Florida Extension Office or garden center to get expert help with this chore. Similar information could be found in a good orchid book. Most gardeners grow their orchids outdoors, hanging in the shade of a tree during the warmer months. Keep your plant moist by misting every other day unless the rains arrive to wet the roots and growing media. Also, feed the plant with a 20-20-20 or similar orchid fertilizer every other week during the warm months. Wet an already damp root system with the fertilizer solution. It’s this easy to grow most orchids and bring them back into flower.
Tom MacCubbin is an urban horticulturist emeritus with the University of Florida Cooperative Extension Service. Write him: Orlando Sentinel, P.O. Box 2833, Orlando, FL. 32802. Email: TomMac1996@aol.com. Blog with Tom at OrlandoSentinel.com/tomdigs.
