Tips for Bare Root Tree Planting
Edited by Len Phillips
Bare root trees are about as basic as trees come. They're affordable, simple to handle, and adapt to transplanting more quickly than trees bought in containers or balled and burlapped.
What are the advantages of planting bare root trees?
- More root mass. Bare root trees can have up to 200% more roots than B&B or container trees, depending on the soil and transplanting history at the nursery. The reason for this is the harvesting machinery for bare root trees digs a much larger root system than the tree spade used for B&B digging. Plus, with bare root trees you won't rob nurseries of their valuable field soil.
- Lower cost. You can plant more trees, less expensively. Without extra labor and materials, bare root trees cost the seller and the buyer less. Bare root trees are one third to one-half the cost of B&B trees. Because they are so much lighter and many more can fit on the bed of a truck, they are cheaper to ship.
- Easier planting. A young tree without soil weighs little, so it is easy to move and plant. Planting a bare root tree costs virtually nothing when done by volunteers with shovels.
What are the disadvantages of planting bare root trees?
- Short planting window. Bare root trees need good soil moisture, so early spring (before bud break) and mid fall (after leaf fall) are the best two digging times and planting times.
- Restricted availability. Some species may not be available bare root, and some nurseries may not have any trees available for bare root retail sale.
- Less storage time. Once they leave the nursery, bare root trees need to get in the ground or be in long-term storage within a week at the longest. With no soil or water, the roots can dry out quickly. If left exposed to sun and wind for more than an hour, the roots will die.
What are the best techniques to follow for bare root tree planting?
- Use any technique you can to reduce the time the tree roots are bare.
- Order 1.5 - 2" (3 - 5 cm) trees to be dug within 24 hrs of pickup at the nursery, otherwise be sure they are stored in a cool, moist place where the roots can be protected from sun and wind.
Why hasn't everyone switched to bare root planting?
First of all, not all species will tolerate bare root planting. This is especially true of trees that have a tap root. Secondly, with municipal tree planting there is an inevitable holding period between digging the trees and planting them. During this period, root desiccation is the most critical disadvantage to planting bare root trees. In the past, people put wet straw around the roots or coated them with a mud slurry. These methods did not prove satisfactory or practical; the straw did not protect fine roots adequately and the mud slurry tended to dry out and chip off. A synthetic, non-toxic water-absorbing compound called hydrogel solves the desiccation problem for that critical time between digging and replanting. Some nurseries also offer pleated plastic bags for protecting bare roots and hydrogel treated roots.
- Bare root trees should be dug during the dormant season.
- Dip tree roots in a slurry of a hydrogel, then store them in large, pleated plastic bags until planting.
- Be sure the nursery has tied the branches up with twine to prevent breakage in transit.
- Keep trees and roots covered, shaded, and moist until actually planted in the ground.
- Snip off any broken roots, then put the tree in a bucket of water for 12 - 24 hours before planting.
- Add a growth stimulant to the bucket of water, such as Superthrive to kick-start root growth.
- Label each tree with its intended address before it gets dipped and bagged so that when the planting labor force picks up the trees to plant, they can simply go to the address on the label. You may also want to label the tree's scientific name, its common name, and the date of planting.
- The planting hole should be no deeper than the root system, but at least three times as wide.
- Do not loosen the soil that will be underneath the root system; instead concentrate on creating loose soil horizontally for the spreading roots.
- Make a cone of soil to rest the tree on and get the tree to the right height.
- Plant the tree so that the trunk flare (where the roots meet the trunk) is at ground level or slightly higher. The trunk flare of bare root trees is obvious and the proper planting depth is easy to determine. However do not mistake the point of graft on cultivars for the trunk flare. The graft must be above ground.
- Spread the roots out evenly over the planting area.
- Fill in the planting hole with the soil just removed, over the roots.
- Do not try to improve the soil with amendments, such as compost. Roots have a tendency not to venture out from the fluffy amended soil and the tree can become root-bound. Filling a hole with amended soil can also create drainage problems. Water tends to stay in the amended area and when the roots get waterlogged, the tree will die.
- When you've replaced half of the backfill, add water to the hole to help collapse air pockets. If the soil does not wash in and around the roots, firm the soil with the wood end of your shovel to gently poke out air pockets. Do not use your foot. You don't want heavy compaction around the roots.
- Finish backfilling, and gently firm soil with water. Make sure the soil is not mounded against the trunk and that the beginnings of the trunk flare is showing above ground.
- Make a saucer, about 3 feet (1 m) in diameter around the tree and fill with water. The water should seep in slowly and reach the depth of the roots. Be sure the tree stays hydrated for the first 24 hours.
- Cover the saucer with wood chips or shredded bark mulch to retain moisture and control weeds, but don't put mulch right next to the trunk.
- Three to four inches (8 - 10 cm) thick is a good depth for mulch over tree roots.
- Consider investing in tree irrigator bags. They hold 20 gallons (75 l) of water and slowly release it to the roots, saving watering time and aiding in tree establishment.
- Fertilizer is not recommended for newly planted trees.
- Staking is not necessary and can even be detrimental for most young trees. The exceptions are an extremely windy site, a tree with an unusually small root system, an unusually large canopy relative to a tree's root system, a tree whose trunk is seriously bowed or in high traffic areas where vandalism is feared.
- Bassuk, Nina, "Creating the Urban Forest: the Bare Root Method.", Ithaca, NY, 2000.
- Christman, Laura, "Bare Essentials: 6 Tips for Growing Bare Root Trees", The Redding Searchlight, Redding, CA January 9, 2010.
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