UMASS Update

Pioneer Valley (Amherst)

General Conditions:

The dry and sunny conditions this autumn season produced a truly spectacular foliar display across the Pioneer Valley. While each autumn season is impressive, the intensity and vibrance of colors this year hit especially hard. But the dry conditions have now become a serious concern. Soils are bone dry in many full sun landscapes, the compounding effect of below-average precipitation in September, October and the first half of November. The US Drought Monitor has designated moderate (D1) drought severity everywhere west of the Connecticut River, while a swath of even worse conditions (severe; D2) characterizes portions of the eastern tri-counties.

While plant water usage is significantly lower this time of year as we settle into the dormant season, drought stress prior to dormancy can result in higher rates of winter injury. The lack of rainfall also makes it more difficult to establish recent transplants. Since 8/20 (our last significant rainfall), recorded precipitation has been paltry in Hampden County (1.0–2.3”), lean in Hampshire County (1.4–2.8”), and insufficient in Franklin County (2.8–3.8”).

The lack of rain, low humidity and gusty winds have also produced numerous brush fires across the Commonwealth, with near daily red flag warnings. One of the largest occurred in Northampton at the Fitzgerald Lake conservation area, where creeping flames charred the forest floor across ~55 acres. It’s a striking end to a prolonged period of wet weather that started in 2023 and carried through the majority of this past summer. Throughout the tri-counties, rainfall was ample (to excessive) during much of the growing season. It’s another reminder of just how quickly soils can dry out and the importance of developing a landscape resistant to drought stress. Specific actions can include soil amendments (e.g. compost) aimed at retaining moisture and mulching to keep the root zone free of moisture-sucking turfgrasses. Proper plant selection and siting is also important to ensure that plants adapted to drier, full sun settings can withstand short-term droughts. Finally, maintaining high vigor by controlling predisposing pest and pathogen issues can ensure plants have all available resources.

Pests/Problems:

Mowing maple, birch and other easily compostable leaves can help to add organic matter to the soil, which is beneficial for trees.

Many needle blight and twig cankering pathogens that can be active during the autumn season likely had a harder time sporulating and spreading due to the prolonged dry and sunny weather. However, the spruce spider mite likely enjoyed a productive autumn season. This cooler season mite thrives during periods of drought. The mild winter of ‘23–’24 was beneficial for garden rodents like voles and their populations have been high this year. Scout for signs of these root and bark eating pests so that repellents can be applied.

Rabbits and deer can quickly negate the annual gains made by plants during the winter months. Depending on local pressure, repellents and fencing should be utilized as needed.

The two previous winters in the valley have seen periods of very wet, heavy snow. As a result, snow loading branch injuries have been common on arborvitae, false-cypress, pine, and yew. Now is a good time to tie up or secure branches that may be injured this upcoming winter. Another form of winter injury that has become more common in recent years is heavy snow sliding off solar panels onto foundation plants. A-frames or other physical barriers should be constructed and put in place soon as early winter snow can often be wet and slushy.