American holly (Ilex opaca) and English holly (Ilex aquifolium) are prized for their glossy, green leaves and brightly colored fruit. Sprigs of both hollies are often used in wreaths, centerpieces, and other Christmas…
Ash trees infected with emerald ash borer (EAB) do not need to be treated or chipped when removed. If you do plan to keep the wood for campfires or fireplaces use it on your property and do not transport the wood to new locations. Any…
Oak wilt is a serious disease that can infect many oak species. It is caused by the fungus B. fagacearum. Red and pin oaks are very susceptible to the oak wilt fungus and can die within 4 to 6 weeks. White and bur oaks…
Most garden areas, including the lawn, vegetable garden, and perennial garden, perform best when they receive an inch of water each week. When this is not supplied by rain, the gardener must do it using a hose, bucket, or sprinkler.
Most garden areas, including the lawn, vegetable garden, and perennial garden, perform best when they receive an inch of water each week. When this is not supplied by rain, the gardener must do it using a hose, bucket, or sprinkler.
The ‘Sunburst’ honeylocust has distinctive yellow-green foliage. Unfortunately, it is not a vigorous tree. It grows slowly and is susceptible to cankers and mimosa webworms.
Cankers, caused by fungal pathogens, are localized…
Shedding bark on some trees is a completely normal development. The bark of most young trees is smooth and thin. As the tree grows, the bark layer thickens with the outermost tissue eventually dying. Continued growth pushes the bark outward,…
Purple, black, and summer-bearing red raspberries that have been badly damaged by rabbits will likely produce little fruit this year. (Purple, black, and summer-bearing red raspberries produce fruit on the previous year's shoots. …
Fire blight is probably responsible for the wilted shoots on your crabapple. Fire blight is caused by the bacterium Erwinia amylovora. Plants susceptible to fire blight include apple, crabapple, pear, hawthorn, and…
The bleached appearance may be due to lace bugs. Lace bugs are sap feeding insects commonly found on the leaves of shade and ornamental trees in Iowa. The most commonly affected trees are hackberry, sycamore, and oak. Adult lace…
Broken or damaged tops are common on young trees due to wind, ice, wildlife, winter dieback or equipment injury. While this damage can affect tree form, most young trees recover well if corrective pruning is done early. The primary goal is to…
The growth on the trunk of the maple tree is likely a burl. Burls are abnormal swellings or growths that develop on the trunks and branches of trees. Burls can be found on deciduous trees and evergreens. The exact cause is…
Shade trees endemic to Iowa or similar ecoregions are listed below. These species can be found east of the Rocky Mountains in North America and Canada. Those native to within Iowa's boundaries are noted with an asterisk (*). …
These shrubs are found east of the Rocky Mountains in North America and Canada. They are hardy to USDA Hardiness Zones 4 or 5. Those native to within Iowa's boundaries are noted with an asterisk (*).
Small ornamental trees endemic to Iowa or similar ecoregions are listed below. These species are less than 30 feet tall and are found east of the Rocky Mountains in North America and Canada. They are hardy to USDA Hardiness Zones 4 or 5.…
The growths on the pin oak are a type of gall. Galls are abnormal growths of plant tissue induced to form by mites, insects, or other small organisms. The galls on the pin oak are called horned oak galls because of the horn-like…
Ash rust is probably responsible for the orange growths on your ash tree. Ash rust is caused by the fungus Puccinia sparganioides. The fungus produces conspicuous swellings on leaves, petioles, and twigs. Infected…
The small, white, popcorn-like objects are likely cottony maple scale. Cottony maple scale is an insect. It is most commonly found on silver maple trees. However, it can also be found on other maples, oak, linden, hackberry,…
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…
Cedar-apple rust is likely responsible for the yellow spots on the crabapple leaves. Cedar-apple rust is a fungal disease. The fungus requires both a crabapple or apple and a cedar (juniper) to complete its life cycle. Crabapple…
The proper planting depth should position the tree so that the trunk flare is level with or slightly higher than the surrounding grade. This is not necessarily the container's height.
When plants produce a chemical that prevents the growth of other plants, it is called allelopathy.
Black walnut is a common woodland and landscape tree in the Midwest that produces an allelopathic compound called juglone which is…
