In our October Tree Care Diary post, we gave our 12 point tree planting guide. It focused upon planting trees whose roots were covered in burlap. These are sometimes called B&B trees or balled-and-burlapped trees. In other words, they come with their roots in a ball of potting soil which is then wrapped in burlap to keep soil and roots contained and from drying out.
However, bare root trees are also a viable option for planting. Bare root trees are often sold in smaller calipers only i.e. generally less than 2 inches in diameter. This is because the failure rate of transplanting trees with a caliper greater than 2 inches is often too high. The stresses placed on a tree during transplantation are significant and are best borne by smaller caliper trees.
What do calipers have to do with anything?
Caliper refers to the diameter of a tree’s trunk at a specific height above the soil or above its root flare. This is often done in the context of nursery trees. Such measurements are taken on small trees at 6 inches above grade. However, if the tree’s caliper is more than 4 inches, its diameter is then measured at one foot above the ground. Such measurements are precise and form a United States national standard to which all respectable tree nurseries adhere.
When is the best time of year to plant a bare root tree?
We firmly believe that October to mid-November is the best time of year to plant any tree, for most latitudes in USA. There remains some warmth in the soil so fragile young roots can develop and establish before less benign much cooler weather arrives in December. There is also great availability of new bare root planting stock being created by nurseries in October. If you choose a fall planting time then get your new tree into the ground well before the first frost is forecast.
Alternatively, springtime is another planting window. However, in spring, more water is needed as the weather is rapidly warming. So if you choose spring you need to be extra vigilant with your new tree. This is another reason why we favor fall as the best time for tree planting. It’ll give your tree a fantastic head start over those planted next year.
4 main advantages with planting bare-root trees:
1. LESS EXPENSIVE – Bare root trees are cheaper to purchase than the same-sized equivalent which has been burlapped. In fact, you can often buy 3 bare root trees for every one B&B tree although the normal saving is around 50%.
2. INCREASED RATES OF SURVIVAL – These trees come with twice as many roots than B&B trees. This helps with reducing post-planting shock so long as the bare roots do not dry out at the nursery or during delivery.
3. GROW QUICKER – Bare root trees are more likely to grow more quickly outside its planting hole. This is because the roots of burlapped trees tend to circle more readily within the clump of soil it came with.
4. MORE VARIETY – As they weigh less and so are easy and less costly to transport, a wider selection of tree species can be found online and via mail order sources. However, just because you CAN buy that exotic, eye-catching tropical tree seedling online doesn’t mean that you SHOULD. Remember: RIGHT TREE RIGHT PLACE. The information contained within our shade tree planting guide in our Tree Care Diary for October (link) still applies. It will help you choose the right shade tree species for your yard and plant it in the right place.
3 disadvantages with bare root tree stock:
1. DESSICATION RISK – Bare roots tend to dry out faster, of-course. If this aspect is not adequately addressed, it severely compromises the chances of the young tree to survive and flourish.
2. EVERGREEN TREES – The survival rates for some evergreen tree types are not great when planted this way. Suggest that you quiz your local nursery for advice. They may steer you towards the Ball & Burlapped option.
3. GIRDLING ROOTS – Some deciduous tree species like red maple and poplar trees are prone to girdling roots and need special handling. The following planting tips, if followed, will help with these trees too. Again, check with your nursery or local arborist for advice and information.
Tree planting equipment you’ll need
1. Your newly purchased and delivered bare-root tree
2. Long-handled spade (a shovel is too big)
3. Watering can or hose
5. Small amount of peat (for clay soils only)
7. Chicken wire (if your tree is exposed to critters, pets and deer) or a plastic tree guard
How to plant a bare-root tree
1. Planting Location – We recommend that this is addressed BEFORE ordering and certainly before you take delivery of your tree. This is because the method we described before to discover the location of underground utility lines in your yard takes a couple of working days. Please refer to our October Tree Care Diary, in this respect. Nothing a growing tree likes more than to delve into a nice moist sewer or drainage line… and destroy it in the process.
2. Delivery of your tree – this can come boxed with roots wrapped in plastic wrapping containing pine tree wood chips or other organic matter such as sawdust. In fact, Arbor Day Foundation’s trees have their roots treated with hydrogel. This is a hydrating gel to stop the roots from drying out. This special treatment is even applied to the 10 free trees you get when you sign up!
Don’t expect a mini tree to be delivered. Expect to see a large stick with a spindly branch or two with some tentacle-like roots bereft of soil. It’s OK, all bare-root trees look like this. Just remember that you can look forward to the four advantages of bare-root trees as mentioned above…IF they’re planted properly.
3. Speed of planting – aim to get your new tree in the ground as quickly as possible, ideally within a day of delivery. You could wait a bit longer if the weather is cool but the roots must be kept moist even with wet newspaper or damp composted material.
4. Prepare your tree – Unpack your tree and carefully measure the breadth of its roots. You’ll need the spread diameter for the next step. 2 hours before planting, soak the bare roots of your tree for 2 to 3 hours in tepid, clean water in a bucket. This will rehydrate those fine roots which may have dried out somewhat in the nursery or during delivery. Don’t kill the tree by leaving it water-logged for longer than a morning or afternoon. No need to prune back any of the roots unless obviously damaged. The rate of growth of your new tree next season will depend on the health and quantity of its roots.
5. Dig your hole – You’ll need to remove grass and roots from a circular area at least 3 times the diameter of the tree’s roots when spread out. Grass is a tough competitor for young trees. It robs them of water, nutrients and oxygen. Then hollow out the exposed earth to form a shallow saucer shape.
Warning – Deep, vertical planting holes are yesterday’s news and will deter tree growth. This is because the roots will find it difficult to breach the abrupt transition into the surrounding soil. Augers are great for setting fence posts but not for trees so we suggest that you keep it in your shed. Latest arboriculture research from Colorado State University shows that a saucer-like shape is best to help the roots’ lateral spread.
6. Build a mound in your hole – You’ll need to form a mound of soil which we call a soil cone in the illustration at the head of this article. Your soil cone will support the tree and help provide a base to gently untangle the roots and spread them out evenly. The top of the ‘cone’ will sit slightly below grade.
7. Plant! – Mount your tree on the soil cone and gently tease out the roots on the soil cone. Cover the roots with the dug soil. Tamp down gently to remove any air pockets in the soil. This will
help to maximize root/soil contact. Ensure that the root flare of your new tree rests above grade when planted. This is very important for the future health of your tree.
Keep some soil by to allow for the ground settling after watering – see stage 11 (below).
8. Do not fertilize! – Our 14-step planting method will help your tree get used to its new soil environment as quickly as possible. Its chances of flourishing into a fine specimen will rise in proportion to the rate of growth of the roots into the surrounding ground. For this reason we do not advocate that the soil is amended with organic or inorganic matter such as compost or fertilizers. There is a real risk that the roots will prefer to remain within the artificially benign environment you have created in a treated and modified planting hole. Remember we want to avoid roots circling (or girdling) the root ball. Instead, we want the roots to spread out in search of the nutrients and water it needs.
9. Treating clay soils – If, however, your soil is of a heavy clay type we suggest the following:
i). Add well-rotted or composted organic matter or peat into the planting hole at a ratio of no more than one-fifth organic to one measure of clay. The peat will help you to break up the heavy clay clumps. This will aid the tree’s roots when growing into the surrounding heavy soil.
ii) To help avoid girdling roots in treated clay planting holes, we advocate digging a wider planting hole to assist with root development i.e. at least 4 times the size of the bare roots when spread.
10. Water – Remember this is late October/ early November so your tree will have no leaves. It will not be transpiring and so its demands for water will be light. The aim of watering here is to help settle the soil near to the roots to maximize soil/root contact. So only water sparingly. After that check your soil every week or so after planting and if moist, do not add additional water. Otherwise, there is a risk of water-logging the roots and so starving the tree of oxygen. This is to be avoided, of-course.
If you are reading this article during the spring, then the weather could possibly be dryer. In which case, check moisture levels in the soil near to the roots every week during the growing season. Water only when necessary to avoid water logging, a tree killer.
When watering, we find its best to keep the trunk and root flare dry. Instead, water the surrounding planting area out to the expected dripline. This will reduce water-logging in one area and discourage girdling roots. It will also encourage the roots to grow out to where the moisture lies.
11. Check soil depth – after applying water to the planting area, check soil depth. Add more soil accordingly to account for any settling. Tamp in gently with the back of your spade.
12. Mulch – Mulching your tree has 4 principal benefits:
i). In fall, it helps to preserve warmth in the ground thus promoting root development and helping your tree get established more quickly.
ii). In winter, it protects the roots under an insulating blanket and reduces the chance of frost damage.
iii). Mulching will also help to regulate the moisture level in your soil by reducing evaporation when it’s dry.
iv). In time, the organic mulch layer will decompose and liberate nutrients which a growing tree can absorb to reach its full potential.
Together these four layered benefits have been shown to accelerate the growth of fine root hairs by no less than 400% by the arboricultural boffins at Colorado State University. This in turn, leads to your tree growing by an extra 20% in height and breadth every growing season; very useful when trying to raise a shade tree.
Apply a layer of mulch no more than 3 inches thick across the whole planting hole except the trunk area.
BEWARE! Dangers lurk in the mulch!! Volcano mulching where the material is piled up the trunk of the tree can and will harm your tree. The root flare, where the bottom of the trunk widens to the start of the root system, needs to be both above grade and also free of mulch. Keep material at least two inches away from the flare at all times. Check this regularly as garden birds and rodents will pick over the mulch layer in search of bugs and critters. They flick out mulch particles in all directions so keep a watch on your new tree. It only takes a couple of minutes to move any material away from the root flare again.
13. Staking – We recommend this only for very windy areas. Avoid the stake rubbing against the tree at all times. And adjust your ties from stake to tree regularly. Use stretchable ties only so that they don’t constrict the trunk’s growth over time.
14. Tree guards – If you will be planting in an area populated by small animals, deer or pets than place some chicken wire around your tree for its protection. Leave plenty of space between wire and tree. If the risk from animals is slight, use a flexible and ventilated plastic tree guard to protect the young tree against mechanical damage during its first year of growth and beyond if it’s planted in a high-traffic area.
More information available from:
– The Bare Root Method (of tree planting) by Cornell University, Ithaca, NY:
– The Science of Planting Trees by Colorado State University
Please see our Tree Care Diary Disclaimer here. Despite our best efforts, our tree care advice cannot be relied upon by everyone in USA, in all locations, all the time.