UMASS Landscaping Update

Pioneer Valley (Amherst)

General Conditions: 

Cool, cloudy and wet conditions have ruled this past reporting period in the Pioneer Valley. But a handful of sunny and mild days have kept spring moving forward. Buds on a variety of trees and shrubs are swelling, and numerous perennials have started growing across the landscape. Apples and crabapples have started leafing out and with low temperatures dipping to the high 20s across the valley on the morning of 4/9, the threat of frost damage will be a concern for the next several weeks. 

Soil moisture is plentiful, and temperatures remain cool, making this an ideal time for transplanting. Turfgrasses are greening up and insects are visible on the milder days. The long-term forecast calls for a continuation of cool temperatures and rain, so plant development should continue at a slow pace.

Pests/Problems: 

Winter injury continues to be a major issue as we progress through the early spring season. The damage is most serious on evergreen shrubs and drought-stressed conifers. Deciduous trees and shrubs like redbud, magnolia and forsythia appear largely unaffected. It's still not clear if flowering cherries were injured, but there is concern about damage to peaches at local orchards. One confounding feature of winter injury is that the damage can be scattered, with badly burned plants adjacent to plants that are relatively unscathed. Rhododendrons, azaleas, hollies (Ilex), doghobble (Leucothoe), and false-cypress (Chamaecyparis) look the worst, with damage ranging from scattered leaf spots and blotches to major canopy dieback. South-facing transpirational burn is also present on white spruce, arborvitae and other conifers. 

Needle blight pathogens of pine (e.g. Septorioides and Lecanosticta) will be active soon. Spruce spider mites have been observed so scout and treat accordingly. Boxwood leafminer larvae are rapidly maturing and can be easily found within infested leaves at this time. Sanitation pruning on Japanese maples should be a priority at this time, if it hasn’t already taken place. Gray-colored, blighted tips are abundant in trees lacking regular care.