While not a regular occurrence, it is not unusual for the foliage of fall-planted bulbs like garlic to emerge a bit early during a mid-winter warm-up. While in Iowa garlic normally begins to emerge from the ground in mid-March to early April,…
Tulips, daffodils, and other spring-flowering bulbs normally begin emerging from the ground in March or early April in Iowa. However, mild winter weather can encourage premature growth. The early emergence of spring-flowering bulb…
The problem may be improper storage. Acorn-type squashes should be stored at a temperature of 50 to 55 degrees Fahrenheit. Some acorn-type squashes will turn yellow when stored at temperatures above 55 degrees Fahrenheit. High…
The African violets may not be receiving adequate light. The proper amount of light is essential for good bloom. Generally, windows with north or east exposures are best for African violets. However, if these exposures are not…
It’s possible to renew some old houseplants by layering. Layering is a procedure used to induce roots to form on a stem while it is still attached to the parent plant. Complete or partial girdling of the plant stem interrupts the…
Improper watering may be responsible for the leaf drop on the poinsettia. Over-watering will cause the lower leaves to turn yellow and drop. Plants that are allowed to get too dry will wilt and also drop leaves.
The sudden death of the poinsettia was likely due to a root rot. Pythium and Rhizoctonia root rots typically occur when plants are watered too frequently and the potting soil is kept saturated. Allow the surface of the potting soil to…
The weight of heavy, wet snow can cause considerable damage to small trees and shrubs. When heavy, wet snow accumulates on small trees and shrubs, gently shake the snow from their branches or carefully brush off the snow with a broom.…
Some tree species, such as maple, birch, and elm, “bleed” heavily when pruned in late winter or early spring. However, the loss of sap does not harm the trees. The trees will not “bleed” to death. Eventually the flow of sap will…
Fertilization is generally not necessary during the winter months as most houseplants are not growing during this time. Indoor gardeners should fertilize their houseplants on a regular basis in spring and summer when plants are actively…
Tulip and daffodil foliage is usually present from late winter/early spring to early summer. The 4 to 6 week period after flowering is especially important. During this 4 to 6 week period, the foliage is manufacturing food for the…
Many houseplants prefer a relative humidity of 40 to 50 percent. Unfortunately, the humidity level in many homes during the winter months may be only 10 to 20 percent.
Misting houseplants is not an effective way to raise the…
The houseplant may be infested with scale insects. These small, inconspicuous insects are covered with shell-like coverings. They attach themselves to stems or leaves and suck sap from the plants. As they feed, the scale insects…
The symptoms suggest the African violet may have root rot. Root rot symptoms initially develop on the lower leaves. The lower leaves turn yellow and droop. As the root rot progresses, affected leaves turn brown and become mushy…
The black growths are probably black knot. Black knot is a fungal disease that occurs on chokecherry, European birdcherry, and several other wild and cultivated cherries and plums. The black growths (galls) can vary from a few inches…
The cold temperatures may have damaged peach and sweet cherry trees.
Peach trees are not reliably winter hardy in most parts of Iowa. Temperatures below -18 degrees Fahrenheit will destroy the flower buds on peach trees. …
The small, white insects are likely whiteflies. Whiteflies are common insect pests of poinsettia, hibiscus, chrysanthemum, and a number of other indoor plants. They are most often noticed when watering or handling a plant. When…
Flower and vegetable seeds can be purchased at local garden centers and other retailers. They’re also available directly from seed growers and producers.
Mail-order/internet sources of seed from seed growers and producers…
The brown growths in your ash tree are probably ash flower galls. Galls are abnormal plant growths induced to form by small insects, mites, or other organisms. On ash trees, a tiny mite causes the male flowers to develop into roundish…
The symptoms of salt injury to deciduous trees and shrubs include stunted growth, marginal leaf scorch, early fall coloration, and twig dieback. Accumulation of salt in the soil over several years may result in progressive decline and eventual…
The white material on the foliage of your African violets is probably powdery mildew. Powdery mildew is a fungal disease that is common on indoor plants, such as African violets, begonias, and poinsettias. Outbreaks of powdery mildew…
"Winter onion" is a general term used to describe onions that can survive the winter outdoors in the ground. The Egyptian onion (also called tree onion and walking onion) produces clusters of small bulbs (called bulblets) at the tops of…
The Emerald Ash Borer (EAB) is an exotic destructive pest that kills all native ash trees (Fraxinus). The loss of ash trees significantly impacts the urban tree canopy. While treatment options are available, some trees cannot be treated…
Yellowing, browning, and dropping of leaves is one of the most vague and difficult issues to deal with because it can be caused by a wide variety of issues. Many of the problems seen in houseplants are not caused by just one factor, they are the…
Light is typically the most limiting factor to successfully growing herbs indoors. Plants will need as much direct sunlight as you can provide. Most herbs need around eight hours of direct light each day when grown indoors. A south-facing sunny…
“Cat grass” is grown by cat owners to satisfy their cat’s desire to graze on green plants. Cat grass is usually common oats or a blend of oats, wheat, and rye grass. It is sold at pet supply stores and garden centers.
Moth orchids (Phalaenopsis spp.) are one of the easiest orchids to grow indoors. Moth orchids grow best in bright, indirect light. Direct sun may actually harm the foliage. Ideal sites…
