Cultural controls are management techniques that help to ensure healthy hemlock trees. They involve simple physical actions property owners can take and in general are most appropriate for ornamental landscape trees.
■ Keep ornamental hemlocks mulched and watered during prolonged droughts. Mulch made from bark or shredded hardwood is more effective and longer lasting than pine straw; it should be applied about 3 inches thick out to the drip line but pulled back from the trunk a couple of inches so as not to encourage fungal growth or other insect infestation. Trees require about an inch of water per week; click here for a Water Needs Chart showing how much water trees of different sizes need -- you'll be surprised!
■ If you go hiking, camping, fishing, etc. in an infested area, your gear and clothes may be carrying adelgid eggs or crawlers, so take care not to spread them to uninfested trees.
■ Don't bring saplings from infested areas onto your property.
■ Don't place bird feeders or deer feeders near hemlock trees; birds and deer can spread HWA eggs and crawlers for long distances.
■ Don't fertilize infested trees until you have the HWA infestation under control as this would encourage new growth and attract even more adelgids.
■ Do normal "forest management" by thinning your hemlocks so the best ones have a better chance to survive. This means cutting hemlocks that are growing too close to each other (unless you're using them for a hedge), that are physically damaged or dead, or that you don't intend to save. It is not necessary to burn, chip, shred, or haul away the cut trees; when the tree is cut, the sap dries up and adelgids that are feeding on the tree will die.
■ Keep a watchful eye on your hemlocks and be prepared to take action at the first sign of woolly adelgids.
■ If you don't intend to use chemical or biological controls, you can remove some of the adelgids mechanically by picking them off, pruning the infested branches, or using a high-pressure water hose.
Healthy hemlocks are not only more beautiful than stressed unhealthy ones, but they also stand a better chance of longer survival if they are attached by disease or insect pests. Because proper planting and maintenance are important for the long-term health of your hemlocks, here are some documents you may find helpful.
■ Caring for Your Hemlock Sapling (updated 2/9/19) -- Handout of easy-to-follow instructions to plant and care for potted hemlock saplings 18" to 6' tall in landscape or forest settings.
■ Caring for Your Hemlock Seedling (updated 1/24/19) -- Handout of easy-to-follow directions for children and their families to plant and care for hemlock seedlings 6" to 18" tall that have been temporarily potted in biodegradable newspaper cups.
■ Planting or Transplanting a Hemlock (updated 2/9/19) -- Complete step-by-step instructions for planting a containerized or balled-and-burlapped hemlock tree 18" to 8' tall or transplanting one 18" to 5' tall from the woods.
■ Rescuing & Potting Hemlock Seedlings & Saplings (updated 4/9/18) -- Complete step-by-step instructions for digging hemlock seedlings or saplings 1' to 5' tall from the woods and potting them for future planting or offering for adoption.
NOTE: Hemlocks that are growing in a forested setting and that are not suffering from disease or insect pests normally do not need supplemental fertilizers once established. They may, however, benefit from extra water if it is possible to get it to them during prolonged periods of drought.
Cultural controls are usually easy for a property owner to do and require only some time and effort. They are an "all natural" approach that can help your hemlocks in their struggle to survive.
Cultural controls will not eradicate the adelgids once they arrive on your property. They provide no long-term protection, and property owners should use them in combination with chemical controls.
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