UMASS Landscape Updates

Pioneer Valley (Amherst)

General Conditions:

Meteorological summer has ended, and students are back on the UMass campus for the fall semester. The Labor Day weekend gave us plentiful sun and high temperatures in the 70s, which made for some downright pleasant gardening weather. The long-term forecast indicates the seasonal cooling will continue and it’s already starting to feel like autumn, with a low temperature in the upper 40s recorded on 9/3. After a blistering hot July in the tri-counties, the mild end to summer was welcome. According to WWLP, Springfield has recorded 21 days this year with temperatures >90ºF. That total includes 9 days in July, which represents almost 1/3 of the entire month.  It’s been dry the past two weeks, with little to no measurable precipitation in the valley since a band of heavy showers on 8/18–19. Shorter days, decreasing sun angle, increasing shade, and lingering dew are all signals that the growing season is winding down.

Goldenrod, black-eyed Susan, panicle hydrangeas, sedums, and many others are providing late season color. Crickets, grasshoppers and katydids continue their nighttime chorus and there’s an abundance of spiders and frogs across the landscape right now. Mosquitos remain abundant, as do a variety of bees and wasps. Junipers, arborvitae, false-cypress and Japanese maples are pushing late season growth.

Pests/Problems:

The upper soil horizon is drying out due to the lack of late August rainfall, but established trees still have plentiful moisture at lower horizons. New transplants should be regularly monitored to avoid soil drying. Generally, deciduous hardwoods should be watered into late October and conifers into late November. This schedule may vary depending on natural rainfall and leaf shed for deciduous plants.

Eastern hemlocks (Tsuga canadensis) are naturally shedding a large volume of older needles right now. In many cases, entire shoots are senescing, and these needles can have a yellow to gold to brown appearance (see photo). They are not diseased but may have been weakened by adelgid and scale infestations. Based on limited studies investigating the longevity of eastern hemlock needles, it’s believed that most needles die after the third growing season. However, there are cases where trees in deep shade can retain needles for more than five years. Generally, hemlocks in full sun tend to turnover needles faster than trees in deeper shade.

Leaf blotch and premature shedding is once again a problem for common lilac (Syringa vulgaris). Many plants are exhibiting pale brown to gray-colored blotches caused by the fungal pathogen Pseudocercospora. Some plants may also be harboring high levels of lilac powdery mildew, caused by Erysiphe syringae. Anthracnose fungi like Colletotrichum may also be responsible, making it a complex of different pathogens.

Chicken of the wood (Laetiporus sulphureus and L. cincinnatus) and the black-staining polypore (Meripilus sumstinei) are actively fruiting on oaks and other deciduous hardwoods.