General Conditions: Sunny weather, variable, on the cool side, with some high winds, prevailed this past week.Not much rain asHanson received only 0.28 inches of rain and soils are beginning to dry out. Remind clients to water water newly planted trees and shrubs. Looking at the plants in Hanson, MA, the cold damage continues to show up with the buds blasted on some of the more tender rhododendrons along with Asian Arisaema like Arisaema ringens and Arisaema sikokianum and outright death of Corydalis ‘Canary Feathers’. There is no sign of growth on Cercis chinensis. This was a tough winter and spring for many plants. The following plants are in full bloom: Halesia sp. (Silverbell), Magnolia fraseri, Magnolia macrophylla, otherlate blooming magnolia hybrids, Cercis canadensis, Cornus florida, Chaenomeles speciosa (Common Floweringquince, Viburnum ‘Eskimo, Viburnum setigerum, Calycanthus floridus (Carolina allspice), Ilex x meserveae (Meserve hybrid Hollies), Rhododendron schlippenbachii (Royal azalea), Fothergilla sp., Syringa sp., Loniceratatarica (invasive),Kerria, Daphne x burkwoodii 'Carol Mackie', Daphne tangutica, Weigela florida 'Versicolor', Iberis sempervirens,Aristolochia durior (Dutchman's pipe), Pulmonaria, Trillium, Convallaria majalis (Lily-of-the-valley), Euphorbia polychroma, Lamium sp., Primula sp., Brunnera macrophylla, Ajuga, Saruma henryi, Phlox subulata, Phlox divaricata, Phlox stolonifera, Myosotis sylvatica (Forget-me-not), Lunaria annua (honesty or money plant), Violets, Dicentra spectabilis (Bleeding heart), Corydalis scouleri, Tiarella cordifolia (Foam Flower), Mertensia virginica (Virginia bluebells), Vinca minor, Galium odoratum (Sweet Woodruff), Hyacinthoides hispanica, Pulmonaria sp., Arisaema dracontium (Jack-in-the-pulpit), Polygonatum sp. (Solomon's Seal), Epimedium sp., Asarum canadense, Stylophorum diphyllum (Wood Poppy), Lamiastrum galeobdolon, Glaucidium palmatum, Corydalis lutea, Mazus reptans and Doronicum sp. The following plants are ending bloom: Sassafras albidum, Kwanzan cherry, Viburnum carlesii (Mayflower Viburnum), Viburnum ‘Mohawk’ and Exochorda racemosa (Pearlbush. Aesculus hippocastanum (Common Horsechestnut), Cypripedium parviflorum (Yellow Lady’s Slipper) and Persicaria bistorta ‘Superbum’ are beginning to bloom and the flowering bracts of the Rutgers hybrid dogwoods (Stellar series) are beginning to open and show color. Lilacs have finally opened and fertilized lawns are green and looking good. Ilex opaca, American holly, has started to shed its older leaves. The yellow leaves falling on the ground often bring questions of concern from clients but this is an annual event for these hollies.
Pests/Problems: Caterpillars are the theme of the season right now. Winter moth caterpillars are mostly at 3rd instar with some 1st and 4th instars observed. It is still too early to predict what the damage might be: some Norway maples have leaves resembling Swiss cheese; other trees show little damage. Many Japanese maples and sugar maples show very little damage, of course this may change as winter moth caterpillars continue to grow and feed on susceptible plants. Continue to monitor and manage as needed. 2nd instar gypsy moth caterpillars were reported ‘ballooning’ or floating through the air this past week in several southeastern communities including: Raynham, Plymouth, Kingston, Carver and Hanson. At this 2nd instar stage, the caterpillars are small, black and covered with tiny hairs which are capable, for some people, of causing an allergic skin reaction (rash). There were 2 reported instances where people developed skin rashes from the caterpillars. Monitoring oaks in Hanson revealed numerous 2nd instar gypsy moth caterpillars feeding on the young oak leaves. Occasionally, winter moth caterpillars were found feeding in the oak foliage along with the gypsy moth caterpillars. However, the gypsy moth caterpillars outnumbered the winter moth caterpillars. (See Tawny Simisky’s Insect Section of the Landscape Message.) Continue to monitor landscape plants for gypsy moth caterpillars and manage as needed. It looks like it will be a big season for gypsy moth unless we get some well-timed rain and the Entomophaga maimaiga fungus kicks in. Roseslug sawfly is active on roses. Monitor the undersides of rose foliage for the small, slug-like larvae, if left untreated, the sawfly larvae will skeletonize the rose foliage. Bacillus thuringiensis (Bt) does not work on sawflies. Elongate hemlock scale was found on Abies koreana 'Horstmanns Silberlocke’, a heretofore uncommon host. This scale is difficult to manage. Fletcher scale is active on Taxus. Monitor pines for European pine sawfly larvae which can decimate the new growth if not managed. The following insects remain active: lily leaf beetle, eastern tent caterpillar, snowball aphid on viburnum, hemlock woolly adelgid, spruce spider mites, snails, slugs, aphids, ants, wasps, hornets, azalea whitefly on azalea, black flies, mosquitoes, honeybees, mason bees, carpenter bees, bumblebees, deer tick nymphs and dog ticks. Remember, the deer tick nymph stage is often thought to be most responsible for transmitting Lyme disease.