We recently planted some new trees. We worked with a local certified arborist and garden consultant, Kyle Henegar (206.293.1270), who taught us some really important facts about planting trees so that they grow well and are healthy & happy.
Things we learned:
1. Most homeowners plant their trees too deep. When you get your trees from the nursery, they are usually either balled and burlapped or in a pot. The instinct is to plant them so the soil level is even with what comes from the nursery. But you actually need to pull the dirt away at the base and expose the trunk down to where it starts to spread out – the trunk flare. That trunk flare needs to be right at the surface of the ground when you plant the tree, or else the tree basically suffocates. Your hole diameter should be 3x as wide as the depth and no deeper than the root ball.
2. Loosen the root ball. Remove the container or burlap bag. Cut and remove any fabric, plastic, string or wire basket. Loosen or score the root ball – gently dig in with your fingers and separate the roots. It is often helpful to use a tool such as a Hori-Hori knife to score the root ball.
3. Back fill with existing native soil. Gently pack backfill, using water to settle soil around the root ball.
4. Stake your tree. When staking is necessary, stake trees with 2 stakes placed about 2 feet away from the tree and secure with wire strung through rubber tubing or use flexible ties. Staking helps support trees in wind and alerts people that this is a newly planted tree and to treat it with care. Do not stake too rigidly. Allow for some trunk movement to encourage the roots to grow stronger. It is important to remove the stakes and wire/tubing after one year so the tree doesn’t get girdled.
5. Don’t over amend your planting hole. Trees generally don’t need a lot of amendment (compost) or fertilizer. It is best to plant in the existing (native) soil; this encourages the roots to grow outwards and become stronger. An over amended planting hole discourages the roots from moving out and properly anchoring the tree. An all-purpose transplanting blend can be used at planting time. It is best to apply the fertilizer lightly over the drip line at time of planting.
6. Mulch. Mulch trees with organic mulch such as arborist wood chips. Steer away from the crappy bark mulch from the home improvement stores. Use a mulch that breaks down over time providing a slow release of beneficial nutrients. Mulch keeps the weeds away, holds in moisture, insulates against heat and cold and provides gradual release of healthy nutrients. It is very important to keep the mulch away from the trunk of the tree – spread the mulch about 3″ deep in a ring around the tree a couple of feet across incorporating the drip line.
7. Watering. Water your trees well while they are getting established the first few years. It is best to water thoroughly yet infrequently to encourage a deep, self-sustaining root system. Water more frequently in the hot summer months and less frequently or not at all in the cold rainy months.