If you’ve been wringing your hands over the onslaught of thugs attacking our trees and wondering how you can help, the time has arrived for you to take action. One simple act will go a long way to keeping our urban forest thriving: plant a tree.
The warming weather and moisture flow is a perfect start to the season, one that gardeners should take advantage of if they would like to put a young tree in the landscape. The soil is getting easy to turn and roots will find their way easily through the ground to establish the saplings in their first year.
Choose your tree based on size, hardiness for our area, and what kind of cleanup it requires. Often those that fruit also shed a bit of detritus on the ground that makes fall cleanup a chore. If you’re limited in time or ability to tidy up after your plant, go with something that doesn’t have as much litter.
Find a list of trees that do well at extension.colostate.edu/docs/pubs/garden/treereclist.pdf. Please note that this was created and published before the discovery of Emerald Ash Borer in Boulder, and includes ash as recommended species.
Small trees establish quickly, especially in spring when the soil warms and has some moisture. If you’re planting trees this spring, give them the best care possible with these tips for planting:
Trees aren’t like furniture; you shouldn’t dig them up and move them around once they’ve been planted. Choose the site carefully for exposure and room to grow. Check the mature height of the tree and put it where it won’t rub against houses or power lines.
Prepare the planting hole so roots can extend out easily; chronically compacted soil should be avoided. Dig the hole in a wide, shallow bowl shape that’s three to four times the diameter of the root ball. Prevent sinking of the tree by ensuring that the bottom of the hole is firmly tamped down.
Remove tree from container, clip any girdling roots, score the root ball, then set tree in place. The “knees” of the root ball – the top edge of the soil where the first major root lies – must be about two inches above the planting hole.
If your tree has a dogleg from grafting (a curve in the trunk just above the graft), turn the root ball so the inside curve faces north. This helps that sensitive spot avoid sunscald.
Pack soil around lower third of root ball to help stabilize it, then backfill the rest of the hole with the soil you removed at digging. There’s no need for mixing the soil with amendments, which can change the texture of the soil, creating a risk for the roots from girdling or water logging. When the hole is half-full of soil, water it to settle the soil around the root ball. Fill in the rest of the planting hole, water it again, and then mulch the tree.
By Carol O’Meara, Colorado State University Extension. CSU Extension together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Colorado State University Extension at the Boulder County Fairgrounds, 9595 Nelson Road, Box B, Longmont, 303.678.6238, e-mail email@example.com or visit ext.colostate.edu/boulder.