Today is Arbor Day in Colorado, an annual event dedicated to the planting and conservation of trees. National Arbor Day is the last Friday in April, but many states observe it on different dates, according to the best time for tree planting.
You can help to celebrate by planting a tree in your community. Here are five tips to get you started:
Find the right spot. A well-placed tree can define your landscape, create views, shade your house and patio and be enjoyed for years to come. A poorly placed tree can crowd the foundation of your house, heave your sidewalks, block views and create a lifelong headache. Be sure to plan before you plant.
Choose your tree carefully. Once you’ve picked your spot, pick a tree that will fit in it. Things to consider include size at maturity, growth rate, root space requirements, proximity to sidewalks, streets and buildings and soil and irrigation requirements. It’s also important to make sure your tree is well-suited to your specific area within Colorado’s climate. Colorado State University Extension (www.ext.colostate.edu) provides fact sheets on Colorado trees; your local nursery can provide recommendations as well.
Determine proper planting depth. Dig a saucer-shaped hole that is at least three times as wide as the diameter of your tree’s root ball. To determine planting depth, find the root flare (a natural swelling on the tree trunk where the first major roots join the tree). This should be immediately visible in bare-root trees; for balled and burlapped trees and container-planted trees, you should remove soil from the top of the root ball until you find it. The depth of your planting hole should allow the root flare to sit slightly above the soil line when planted.
Plant correctly. If you’re planting a bare-root tree, first mound some backfill dirt in the bottom of the hole and spread the roots over it. For balled and burlapped trees, you should set the tree in the hole, stabilize it by firming a circle of soil around the root ball, and remove any burlap, string, plastic or other materials from the upper 12 inches or two- thirds of the root ball (whichever is greater). For container-grown plants, remove the container and check the roots. If roots are wrapping around themselves, score them with a knife or your fingers prior to planting, then poke holes in the edges of the planting hole to enable root penetration. In all cases, if you amend the backfill soil with organic matter be sure to mix it in thoroughly before you backfill the tree. When you backfill, make sure you keep the root flare slightly above the soil line, hold the tree straight while you fill in the hole with soil and water it thoroughly.
Create a watering basin and mulch around your tree. In dry landscapes, use excess soil to form a ring around the planting area. This will hold water around the base of the tree and promote soaking into the soil. Don’t use basins in well-irrigated lawn situations where it will hold more sprinkler water than new trees need. Adding 2 to 3 inches of mulch around the base of the tree can help to stabilize soil moisture levels, limit competition from weeds and protect young trees from injury from mowers, trimmers and weed eaters. Because heaping mulch chips against the tree can invite bark decay, be careful not to mulch within 6 inches of the trunk.
Rebecca Winning is a master gardener at Colorado State University Extension in Denver.
