Q: I recently bought an older home and need help in identifying a large shrub that is producing abundant and large clusters of pea-shaped flowers that are bright red. There are small thorns on the stems. Can you identify this shrub?
A: This shrub is commonly known as fireman’s cap or coral tree. Its botanical name is Erythrina crista-galli. Fireman’s cap is subject to freezes and may lose its top if freezing weather occurs, but it is usually root-hardy. While it is typically a large shrub, it can develop into a small tree which can reach 20-25 feet if not damaged by cold weather.
Blooms are large 18-24 inch panicles of crimson red flowers that are shaped liked a fireman’s cap. Blooms are produced through the summer. Fireman’s cap tolerates dry or wet conditions well. It is heat and drought tolerant once established. The fireman’s cap is a low-care shrub that prefers full sun and a well-draining soil. The flowers also attract hummingbirds in spring and summer.
Q: I have three large, healthy hydrangeas that have not produced any flowers over the past two years. Any ideas on what caused this?
A: Hydrangeas require full sun, adequate moisture and adequate soil fertility for best bloom. If you are meeting these needs, the only other obvious cause for the lack of blooming is improperly timed pruning. Hydrangeas look best when periodically pruned. Be sure to prune right after they finish blooming because flower buds are formed in late summer and fall. Remove stems that have bloomed and leave stems that have not bloomed. The stems may look dead in winter, but they contain the leaf and flower buds for next spring.
Q: When my air conditioner unit started running overtime, I called an AC service company to check it out. The repairman told me that the cooling coils on my outside AC unit were clogged with cotton produced by cottonwood trees. Why does this happen?
A: If you have cottonwood trees growing in the neighborhood, you should periodically inspect the coil fins of your outside AC unit for blockage by cotton produced by female trees. Many people do not realize that there are male plants and female plants in some plant families. Such plants, including cottonwood trees, are called dioecious.
Male cottonwood trees produce pollen, while the female trees produce an abundance of seeds which are surrounded by ultra-light white fluff hairs that look like cotton. The “cotton” is an appendage to help disperse the cottonwood seeds so they do not fall at the base of the mother tree.
As seeds drop from the parent tree, they are carried by wind away from the mother tree. In fact, the tree seed that often stays in flight the longest is that of the cottonwood. The tiny seeds can be carried by air currents for several days. Unfortunately for us city dwellers who are creatures of comfort, the cottony-like seeds of cottonwood often end up clogging the coil fins of our central AC units.
Be sure to keep the outdoor condensing unit free of cottonwood seeds as well as grass clippings and dirt buildup. Sufficient air cannot pass over the outdoor coil for proper cooling operation if it is clogged, which causes the unit to run longer and work harder. The coils can be easily washed down with a garden hose but shut off power to the unit before you do so.
Q: There are large insects that look like bumble bees that are chewing holes in the wood trim under a porch. What can I spray on them to keep them away?
A: It is the season for carpenter bees which are very similar in appearance to bumble bees. After mating, the fertilized females excavate tunnels in wood and lay their eggs within a series of small cells.
Because a carpenter bee does not eat the wood she is boring through, it is difficult to stop her with surface applications of insecticides. There are no repellents sold for this purpose. Liquid sprays of carbaryl (Sevin) or a synthetic pyrethroid (e.g., permethrin or cyfluthrin) can be applied as a preventive to wood surfaces which are attracting carpenter bees.
Carpenter bees prefer to attack wood which is bare, weathered and unpainted. The best option to deter the bees is to paint all exposed wood surfaces, especially those which have a history of being attacked.
Q: We purchased several loads of hardwood mulch to go around our shrubs. It had only been down for a few weeks when orange and yellow mounds of growth appeared in it. It looks like some type of disease because it is coming up in the middle of our flowers. What can I spray to stop its growth?
A: With our rainy and warm weather conditions over the last few weeks, this has been a frequent complaint. This growth is a slime mold which is a primitive type of fungus. It is harmless to plants. Although unattractive and somewhat alarming, it will dry up in just a few days. You can hasten its demise by breaking up the mound with a rake. This fungus is associated with the decomposition of hardwood bark. As the bark ages over the summer, you will see less of it.
NOTE: Attached also is a file (DSCN4348) in JPEG format. If used, suggested caption is as follows:
Fireman’s cap is a low-care shrub that preforms best in full sun and a well-draining soil. The crimson-red flowers are shaped like a fireman’s cap and attract hummingbirds in spring and summer.
PHOTO CREDIT: William M. Johnson
Thanks,
William
_____________________________________________________________________________
Dr. William M. Johnson is a horticulturist with the Galveston County Office of Texas A&M AgriLife Extension Service. Visit his Web site at http://aggie-horticulture.tamu.edu/galveston/index.html
398
previous post
