While pruning the roots of a plant may sound scary, it's sometimes necessary. If done properly, root pruning can improve the plant's growth and overall health. This is especially true with container plants that can become “pot-bound,” with the roots girdling around the inside of the pot.
Trees are made stable by their root system. Its main structural roots, which are larger, begin close to the trunk then flare out. This is called the "root flare." The closer the roots are to the tree, the more important they are for keeping the tree upright. Cutting these roots can lead to instability.
Roots packed tightly in a pot don't take up nutrients efficiently. To promote good nutrient absorption, trim the roots and loosen up the root ball before replanting. Use a sharp knife or pruning shears for this job, removing as much as the bottom third of the root ball if necessary.
Many plants will survive and recover from root damage if the damage does not exceed 1/4 of the total root zone. Most of the important feeder roots of trees or shrubs are within the upper six inches of the soil. If damaged, the uptake of water and nutrients is restricted reducing growth.
Don't remove more than 1/3 of anchoring roots.
Avoid removing large, or anchoring, roots. Anchoring roots provide a lot of support and branch off into many smaller roots. If you must remove some, don't remove over 1/3 of all anchoring roots.
Avoid cutting any taproot, corm, or bulb your plant has, or the plant will die. Cutting through the outer roots growing in a circular pattern will keep the plant from strangling itself as it grows. Take time to evaluate the health of the roots.
Surface roots make it difficult to mow grass. It is tempting to cut these roots off to make mowing easier. A few small roots can be severed on well-established trees. Cutting or damaging roots larger than about one inch diameter could cause harm to the tree.
Roots absorb water and minerals and if the roots are cut off the plant wont get water and minerals and it will die.
With roots pruned, the plant is ready to go back into its pot. Potting soil that is dry or only slightly moist sifts most readily in among the roots. First I put enough soil in the bottom of the pot that the base of the plant's stem will sit a half to one inch below the level of the pot's rim.
Rooting will generally occur in 3-4 weeks but some plants will take longer. When the roots are 1-2 inches long or longer the cutting is ready to be potted up. This plant has heavy rooting and is ready to be moved to a pot with potting soil.
Once you've figured out which houseplants need repotting, it's a good idea to water them well the day before you plan to upgrade their containers. A thirsty plant is a stressed plant, and already unhappy plants won't adjust well to the move. Plus, a damp root ball will be easier to work with than a dry one.
The idea is to soak the plant for several minutes in water prior to planting. When you plant, fill up a large bucket with water–preferably rainwater since it does not have any of the chlorine or other chemicals of municipal water. Take the plant out of its pot and gently pull any encircled roots away from the plants.
If there is no green anywhere in the stems, roots can still be checked. Carefully dig the plant from the soil and look for roots that are light, supple, and have little to no scent. Dead roots will either be mushy and smelly or dry and brittle.
Root cuttings are used to propagate plants that naturally produce suckers (new shoots) from their roots. This technique has several advantages: Root cuttings require no special aftercare. Large numbers of new plants can be generated from each parent plant.
A potted plant should be root-pruned whenever the plant's roots grow to the extent that they entirely fill the pot and begin to circle around the inside surface, or if the roots visibly escape through drainage holes.
Every year cut back some of the longest vines to keep your Pothos in check. But remember that the roots will keep growing even if you snip the foliage. If you don't want to keep moving your Pothos into larger containers, you should give it a root pruning every couple of years.
Dwarfing is a process in which the plants become significantly smaller. This effect can be genetic or hormonal. The root tip secretes hormone called cytokinins which is a shoot promoting hormone. If the roots are cutted the production of cytokinins is reduced.
Other indicators of a pot-bound plant include roots growing out of the pot's bottom drainage hole, as well as water that pools on the soil's surface. Roots that encircle the pot prevent the absorption of water. Leaf drop, failure to thrive, and lack of new growth are also indicators that it's time to repot your plant.
You should remove these roots before returning your plant to its pot. With your sanitized shears, trim dead roots about an inch above the point where they have begun to die. This trimming gives the plant a chance to regrow healthier roots once replanted.
If you do, you'll be robbing your soil microbes of a good meal and degrading your long-term soil fertility. You'll also be inadvertently removing a lot of the good microbes that live around the root systems of your old plants – microbes that could help your future plants.
Most people are familiar with growing new plants from seeds, but new plants can also be created by cutting off a portion of an established plant. This “cutting” is placed in an environment that encourages it to produce new roots and/or stems, thus forming a new, independent plant.
Start by using a soil knife to loosen the tree in its pot, then tip it on its side to slide the root ball out of the container. With a pruning saw or sharp knife, slice about 2 inches off the bottom of the root ball to get rid of circling roots massed at the bottom of the pot.
Roots that appear brown, black, soft or rotted indicate an unhealthy plant. A rotting, foul odor may also be present. The problem could have developed due to any of the following: Over or under-watering.