UMASS Landscaping Update

Pioneer Valley (Amherst)

General Conditions:

Summer rolls on in the Pioneer Valley and as July winds to a close, it’s likely been a month for the record books. The two-week stretch from 7/4 to 7/18 was one of the most prolonged periods of heat and humidity many of us have experienced in recent memory. The humidity was really the dominant feature, as dew points were regularly in the mid-70s to even ≥80°F on certain days (7/6, 7/9–10, and 7/15). As a result, heat indices frequently peaked in the upper 90s to >100°F and scattered thunderstorms were a regular occurrence. Then, like some meteorological crescendo, severe storms pummeled the valley (Franklin County, in particular) on 7/16 and 7/17, downing power lines and trees, creating washouts, and flattening tall plants across the landscape. On the upside, many areas received a good soaking rainfall. Rainfall totals varied significantly over this reporting period, but many weather stations in the valley recorded 2–4”. Overall, most gardens look outstanding this year with abundant flowering and strong growth. There are hints of late summer across the landscape with the sound of crickets and katydids taking over the early evening hours, and heavy fog blanketing the Connecticut River in the morning.

We are entering a prime period for transplanting conifers, especially pine and spruce. The current season’s growth is mostly to fully hardened off while new root production continues.

Pollinator activity is still very high, and a range of social and solitary wasps, bees and flies can be encountered. Mosquito populations remain high due to the regular rains.

Pests/Problems:

Continue to closely scout plants for any signs of insect feeding or symptoms of disease. Many plants are starting to bear the marks of the growing season with various foliar blotches and scattered branch dieback. Heat scorch can be found on various plants, including stewartia and rhododendron. Anthracnose diseases are abundant this year and symptoms can vary significantly by host and location. Stem and branch cankering diseases are always a problem and canopy flagging is visible on hardwoods and conifers. It’s another potent year for apple scab, caused by Venturia inaequalis. Older, interior canopy leaves that are diseased continue to shed. Wood-rotting fungal pathogens are appearing more frequently around the base of infected trees right now. Take note of particularly destructive fungi, such as chicken of the woods (Laetiporus) and Berkeley’s polypore (Bondarzewia).

Crabgrass is exploding with growth due to the heat and rains. Many cool season turf grasses are in some stage of dormancy or significantly reduced growth but remain green.