General Conditions: The warm weather (mid-80’s) from Wed. May 25th - May 28th certainly accelerated plant growth, however with the extremely dry soils, it also stressed unirrigated landscape plants and plants that had just started to flower were wilting. Relief from the heat came on Sunday, May 29 when temperatures dropped to the 50’s -60’s followed by rain on May 30th. Hanson received 1.5 inches of much-needed rain. The following plants are in full bloom:
Styrax obassia, Rutgers hybrid dogwoods (Stellar series), Prunus serotina (black cherry), Aesculus x carnea (Red Horsechestnut), Liriodendron tulipifera (Tuliptree), Cornus kousa, Cornus controversa, Cornus alternifolia, Laburnum watereri (Goldenchain Tree),Wisteria floribunda (Japanese Wisteria), Robinia hispida, Calycanthus floridus (Carolina allspice), Kerria, Weigela florida, Aristolochia durior (Dutchman's pipe), numerous viburnums (including Viburnum opulus, V. plicatum var. tomentosum (Doublefile viburnum), V. sargentii), Beautybush, Indigofera sp., Abelia mosanensis, Chionanthus virginicus, Cytisus scoparius (Scottish broom), Rhododendron, late lilacs like Syringa x prestoniae ‘James Macfarlane’ and Syringa ‘Miss Kim’, Clematis, Paeonia (Peony), Allium, Salvia ‘May Night’, Baptisia australis and Baptisia hybrids, Tradescantia , Anemone canadensis, Amsonia sp., Thalictrum aquilegifolium, Oriental poppies, Lupine, Columbine, Geranium sp., Buglossoides purpurocaerulea, Doronicum sp., Lamiastrum galeobdolon, Lamium, Dianthus sp., Dicentra spectabilis (Bleeding heart), Saruma henryi, Arisaema (Jack-in-the-pulpit), Cypripedium sp.,(Lady’s Slipper), Polygonum bistorta ‘Superbum’, Corydalis lutea, Siberian Iris, bearded iris, Phlox subulata, Phlox divaricata, Phlox stolonifera, Valeriana officinalis, Myosotis sylvatica and Centaurea montana.
Cotinus obovatus and Cotinus coggyria are also in full bloom with their small, rather insignificant flowers, to be followed by the interesting ‘smoke’ they produce following full bloom. Multiflora rose has started to bloom and Oriental bittersweet and burning bush are in full bloom. Now is a good time to remove these Massachusetts invasive plants along with barberry and autumn olive which just completed bloom. The yellow pollen of eastern white pines has been steadily falling, filling the air and covering everything in sight.
Pests/Problems: According to staff at UMass Entomologist Dr. Elkinton’s lab, winter moth caterpillars are just about done feeding for the season and have pupated, except for a few spots on the north shore. Scouting here in Plymouth County, I did not find one winter moth caterpillar. Foliar damage is present, yet sporadic, but by no means as extensive as in previous years. The early winter moth egg hatch April 1, followed by the freezing snow and then the extended winter moth egg over several weeks, combined with delayed foliar emergence, may have played a part in reducing the number of caterpillars. The upper canopies of some trees are thin but overall most trees look good. However, gypsy moth caterpillars may become problematic and cause further damage, especially in those areas where they were in high densities last year. There are many gypsy moth caterpillars in the landscape and most are in 3rd instar and a few in 2nd and 4th instars. They will continue to feed for a few more weeks and the bigger they get the more they eat, so monitor now and manage if needed. Gypsy moth caterpillars were found in high numbers on oak and were also in lower numbers on maples, blueberry, Fothergilla, etc. At this time they are mostly found feeding on the underside of the leaf. Cottony camellia scale (also known as Cottony Taxus Scale) is active on Taxus and Meserve hollies; monitor and manage as needed. We should soon, if not already, be seeing the emergence of the White-spotted pine sawyer, a native beetle that does not damage trees like the ALB. The White-spotted pine sawyer is often confused with the Asian Longhorned Beetle (ALB) but is merely one of the “ALB look-alikes”. http://massnrc.org/pests/albdocs/ALBLookalikes_Massachusetts.pdf
The small white maggot of the Orthacheta Bud Fly, sometimes referred to as the Iris bud fly, has been found in the developing buds and flowers of Siberian iris, Iris pseudacorus and bearded Iris. The maggots feed in the developing buds, and the emerging flowers are tattered and look terrible. The maggots will go down into base of the flower then into the stem. Not much can be done to prevent this pest, but removing and destroying the newly damaged flowers and stems, may help manage it. Lily leaf beetle adults, as well as the red eggs and disgusting, feces-covered larvae, are active on true lilies. If not managed, the beetles and larvae will destroy the lilies. Roseslug sawfly is still active and will skeletonize rose plant foliage if not managed. Azalea sawfly is almost done feeding for the year; not as much damage to plants at the Hanson site, as in previous years. Euonymus caterpillars (cream colored with black spots) remain active, feeding on the new foliage of euonymus and expanding their webs as they feed.
Mosquitoes are numerous this year; empty containers of water to help prevent breeding and consider using Bti (Bacillus thuringiensis israelensis) in birdbaths, plant saucers, etc.
The following insects remain active: elongate hemlock scale, hemlock woolly adelgid, spider mites, spittlebugs, aphids, deer tick nymphs, dog ticks, biting flies, carpenter ants, azalea whitefly, snails, woolly beech aphid, ants, wasps, hornets, carpenter bees, and bumblebees.
Monitor the foliage of ‘Arnold Promise’ witchhazel for Phyllosticta hamamelidis (Witchhazel blight); look for irregular shaped brown splotches. http://extension.illinois.edu/hortanswers/detailproblem.cfm?PathogenID=54
Several people have observed that numerous Eastern white pines are turning brown and these pines are not near roadways where roadway salt may be a factor. (See Nick Brazee’s Disease Section of the Landscape Message).
The shiny green Azalea leaf gall (Exobasidium vaccinii) continues to show up on deciduous azaleas; hand-pick and destroy the galls before they turn white. The following weeds are in bloom: ground ivy, oxeye daisy, cinquefoil, narrowleaf plantain, buttercups and veronica. Wild turkeys, chipmunks and rabbits are numerous in the landscape.