Take steps to control leaf damage on crape jasmine
Question: Our crape jasmine develops holes in its leaves that then turn yellow and drop. What is the cause and a control?
Answer: Crape jasmines are known by many names including crepe jasmine, poor man’s gardenia and pinwheel flower. Each refers to an evergreen shrub with white scented flowers having multiple ruffled petals. Your email photo showed leaves with yellow spots that enlarged and turned brown. The dead spots eventually dropped out, leaving a hole.
Various fungal leafspot organisms can cause this decline, most likely to occur with older leaves that are losing their resistance to disease. It also occurs when plants are without adequate air movement during periods of high humidity. Plants lacking needed fertilizer often show more leaf spots. Applying a fungicide may help prevent further leaf damage. Also, make sure the shrubs receive three to four fertilizer applications a year.
Q: I purchased a persimmon tree a year ago and was told it would be bearing in two years. The leaves are turning brown and it is not doing well. Any suggestions?
A: Fruiting within two years is a bit hopeful, but with good care you might get persimmons in three to four years. A lack of good growth may be a planting problem. Make sure the tree is planted at the proper depth, with the top of the root ball at or slight above the normal soil level. Then keep the tree moist but not overly wet in a welldrained soil.
Persimmons need full sun exposure for best growth. Fertilize your tree in March, May and September with a fruit tree fertilizer at the label rate. Be careful not to over-fertilize your tree, as too much delays flowering and fruiting. The trees do yellow and drop their leaves during fall. They may also be affected by fungal organisms, causing browning of the leaves in late summer and fall, which can normally be ignored.
Q: We have access to cow, chicken and horse manure. Does it matter which one we use in the garden?
A: Speaking from experience, it does not seem important which manure you use. Many of us have used plenty of cow, horse, chicken, turkey, rabbit and guinea-pig manure and they all help fertilize the plants. Poultry manure is usually twice as concentrated as that of other farm animals, so you only need about half as much. Rabbit manure is four times more concentrated and guinea-pig manure is said to be similar.
Since most of us do not live on a farm, we may be susceptible to organisms associated with the farm animals and their manure, so current recommendations are to compost fresh manure before use. This normally requires about 90 to 120 days, following good composting practices. Then apply about 25 pounds of cow and horse manure to each 100 square feet of garden space and 12 pounds of poultry manure tilled into the soil prior to planting. Manure can also be used as a side dressing at 5-pound and 3 pound rates, respectively, per 100 feet of row.
Q: Each year when I bring a Christmas cactus with blooms indoors, it flowers a little but then drops most of its remaining buds. What can be done to make it last longer?
A: Don’t feel too bad, but your Christmas cactus is not happy in your home. This would be the same for Thanksgiving and holiday cactus too. The shock of moving from conditions outdoors to inside stresses the plants and they drop their buds. Maybe you can allow the plant to remain outdoors in a spot to be seen from a window. Or, add it to a patio or porch under conditions similar to where it was growing. Providing another spot indoors with light, temperature and humidity similar to its outdoor spot would work too. This problem is also common with plants brought home from the garden center.
Q: I really like zinnias, but when I add them to bouquets, the water sours and the flowers decline. How can I keep them fresh a little longer?
A: Remove the lower leaves from zinnia stems and your blooms will likely last a lot longer. Those big, flat leaves seem to harbor organisms that, when submerged in water, cause the foliage to rot and turn the water a dark color. You may also try adding a floral preservative to help extend cut-flower life.
Q: One of the palms in our yard is full of small ants. Are they causing a problem and what is a control?
A: Ants can become very comfortable in palms hiding among the fronds and living off plant sap and insect residues. Generally, they cause little harm but can become an annoyance. When needed, help keep the ants under control by removing loose palm fronds, old flower stalks and other debris where they may congregate. If ants remain a problem, apply a general insecticide that lists ants as one of the pests controlled and has instructions for use with ornamental plants. Spray areas where the ants may hide to obtain the best control.
Q: Several of my herbs growing in containers made it through the summer but have lots of dead stems. Can they be saved?
A: Herbs should rebound with lush new growth during coolish weather ahead, but your plants may need special care. First, prune off all dead or declining portions. With many like mints, oregano, thyme and similar, this may mean cutting them back close to the container.
Check to see if they need a new container. When roots fill the pots, give them an inch or two larger container. You may consider dividing the herbs and making several pots. Lastly, apply a slow-release fertilizer following label rates to feed the plants for several months. Also, keep the soil moist.