GREEN TIPS
Department of Horticulture - Michigan State University

LANDSCAPE MANAGEMENT CALENDAR
APRIL: First Signs of Spring
Planting

Plant bare root, balled and burlapped, balled and potted, and container-grown ornamental landscape plants. Bare root plants should be dormant. Spring has become a traditional time for planting because environmental conditions favor planting. Soil and air temperatures should be above freezing. Plants adapt readily to the intensity of spring sunlight and are less likely to be stressed by dry weather.

Transplanting

Dig plants that were root pruned in the fall. Deciduous plants may be moved bare root before bud break, but broadleaf and narrowleaf evergreens should be moved balled and burlapped or balled and potted. Moving may be done whenever soil and air temperatures are above freezing. Root prune plants that you intend to move in September or October.

Pruning

Thin and rejuvenate overgrown or unhealthy deciduous plants to direct and control new growth.

Fertilizing

Fertilizer may be broadcast around ornamental landscape plants as the ground begins to thaw.

Watering

Irrigate newly planted, actively growing ornamentals any time there is less than 1 inch of weekly rainfall. Apply water at the rate of 1 quart per square foot of planting area on poorly drained soils. On well drained soils, use a half-gallon of water per square foot. Newly planted ornamentals not yet actively growing can be injured by overwatering.

Plant protection

For newly planted ornamentals, you may apply a pre-emergence herbicide before spreading a 2- to 3-inch layer of mulch over the soil in the bed or around trees. Level winter mulch and use the excess to thicken thin spots in beds and around trees for a summer mulch to conserve moisture and prevent weed seed germination.

Rodent tree trunk guards, rose cones and fabric wind screens around evergreens should be removed when freezing temperatures are no longer a threat.

Pest control

Warning! Not all formulations of all recommended pesticides are labeled for all suggested uses. Buy formulations that are labeled for the specific pest problem. Follow all pesticide label directions and precautions.

When a particular pest becomes active depends on the weather conditions in your area. The pest management guide gives general guidelines for a broad geographic area. Depending on your location, a particular pest may appear early or late within the month(s) in which the pest is listed.
 
 
Pest Common Hosts Controls
Insects
adelgids spruce Dursban, lindane, malathion, Sevin
aphids most ornamentals Diazinon, Orthene, malathion, Sevin, superior oil
leaf miners arborvitae, birch, hawthorn, holly, spruce Diazinon, Orthene, Sevin
mealybugs taxus malathion, Orthene, superior oil
scales ash, euonymus, fruit trees, hackberry, hawthorn, hemlock, juniper, lilac, linden, maple, mountain ash, oak, pachysandra, pine, poplar, rose, spruce, willow Orthene, malathion, Sevin, superior oil
tent caterpillars crabapple, flowering & wild cherry, fruit trees Orthene, Sevin
Diseases
anthracnose ash, maple, oak, sycamore Cleary's 3336, Captan
black knot fruiting & ornamental plum Cleary's 3336, Captan
Botrytis blight rose Cleary's 3336, Captan
canker & rot most ornamentals Prune out infected plant parts.
crown gall euonymus, rose Destroy infected plants.
fire blight cotoneaster, crabapple, fruit trees, hawthorn, mountain ash, pyracantha Prune out infected plant parts.
leaf spot most ornamentals fixed copper
powdery mildew most ornamentals Cleary's 3336, sulfur
rust apple, crabapple, hawthorn, juniper, rose Ferbam, 
scab crabapple, fruit trees, mountain ash, pyracantha Cleary's 3336, Captan, Daconil
twig blight juniper Cleary's 3336
wetwood elm, maple no effective chemical or cultural control
Weeds
many germinating annual & perennial weed seeds many ornamentals Eptam, Princep, Treflan



Source: MSU Extension Bulletin E-1947