How to Treat Spruce Spider Mites
Gardeners aren’t the only ones who like the dwarf Alberta spruce. Sadly, it’s also popular with spruce spider mites that attack in spring and fall, unlike regular spider mites, which are active in hot, dry weather. If your spruce has yellow speckles or brown needles at its base or near the trunk, spruce spider mites are most likely the culprits. To find out if spruce spider mites have moved in, shake a browning branch over a piece of white paper. If you see tiny specks moving around, squish some with the tip of your finger. If the resulting goo is green, they’re spruce spider mites. But there’s good news: If you see red, they’re beneficial insects that are already eating up the spruce spider mites, and you can let them get on with their cleanup work. If the beneficial insects are not on the job, suffocate the mites by spraying the entire tree with horticultural oil, like Monterey Cultural Oil ($15, The Home Depot).
Treating Dwarf Alberta Spruce Winter Burn
Browning that moves from the tip of a branch toward the trunk is a sign that winter weather has dried out the needles. This can happen on sunny winter days when the ground is still frozen, making it impossible for the tree’s roots to pull up more water. Brown needles will show up on the south or west side of the tree, where it received the strongest rays of the sun. To keep this from happening, be sure to give your dwarf Alberta spruce plenty of water in the fall (especially if you don’t get much rain) so the roots can soak in the moisture before the ground freezes. Also, spread two to four inches of mulch around it, starting three inches from the trunk and going out to the ends of the branches. The mulch helps hold water in the ground longer, and it evens out the cold soil temperatures.
If Your Tree is Completely Brown
If the tree is still mostly green, future growth at the ends of the branches will probably make up for the brown needles, which will eventually fall off. If the whole tree has turned brown, replace it and start over with better planting and watering, in a different part of your garden, or with another kind of evergreen. Plant a dwarf Alberta spruce in early spring or late summer, so the roots can get growing before summer heat or winter cold. Choose a spot where it won’t get the worst winter winds, as those can also dry out the tree’s needles. Buy It: Dwarf Alberta Spruce Tree ($30, The Home Depot)
Treating Trunk or Root Damage
A dwarf Alberta spruce that’s turning brown at the top is telling you there’s a problem with the trunk or the roots. Check to see if weed whackers have sliced the trunk, or animals have chewed the bark. If most of the bark is gone from the base of the trunk, the tree will have to be replaced. If the tree is planted in a part of the garden that gets either waterlogged or completely dried out, the roots may have rotted or become too dry, unable to provide enough water to the tree.
