How to Transplant Everything in Your Garden: Flowers, Shrubs, and Trees
Transplanting anything, seedlings, starter plants, perennials, trees, or shrubs, is an integral part of gardening. You want your new plants to grow well in their new home. Making sure they’re appropriately transplanted helps to ensure their success. Here are some tips for transplanting everything from seedlings to starters to shrubs and trees–– and even transplanting an established shrub or tree to a new site in your yard.
General Transplanting Tips
Keep an eye on the weather when you’re planning to transplant any plants. Warm damp soil is ideal; cold and very wet soil can be a shocking transition for your plants. If you’d like to speed up the soil warming process, you can lay black plastic over the area you’ll be planting in to collect the heat from the sun for a few days.
Before you start transplanting, make sure you have prepared beds and pots for planting. Loosen up the soil, aerate, and add any amendments that might be needed. If the soil where you’re planting is dry or you’re potting soil is dry, make sure to rehydrate it before planting. It’s usually best to do this the day before planting, or at least a few hours so that the soil can rehydrate evenly through the whole area or container.
Choose a cloudy or overcast day for planting or, better yet, plant in the evening. Yes, we said to make sure the soil is warm because cold can be stressful for plants, but the hot direct sun is also stressful. If you need to get something planted on a hot day, make sure you water it well, and then set an umbrella over it to shade for the rest of that day.
Transplanting Seedlings
If you haven’t hardened off your seedlings yet, start ASAP. Give them at least 5-7 days outside during the day, inside at night, before putting them in the ground, so they aren’t shocked by the extreme environment. Water your seedlings before transplanting; damp soil comes out of pots easier. Don’t pull on the plants by their stems. Squeeze around the outside of the pot to loosen the soil. If that doesn’t work, slide a butter knife along the outside edge of the soil. Cut off any roots hanging out the bottom drainage holes of the container.
Use the fingers and palm of one hand to support the stems and soil in your containers, then tip the container almost upside down and give it a few gentle squeezes. The root ball should slide out into your hand easily. If you must grab some plant parts to pull them out, grab leaves. They can grow new leaves if damaged; they can’t grow a new main stem. If you had multiple seedlings in the same container, gently tease them apart to separate the roots.
For most seedlings, plant them in a hole as deep as the pot they were growing in. So, they are at the same soil level as they were in the pot. Fill the hole halfway with water, pop the plant in, and backfill with soil. If you want to add fertilizer at planting time, a root fertilizer will help them establish well. You can plant tomatoes much deeper–– right up to the bottom of the first set of leaves. Fill your planting hole half full with water. You can add a root fertilizer if you like and then plant your seedlings, firming the soil around them.
Transplanting Starter Plants
Transplanting starter plants, whether perennial or annual, is similar to seedlings, but usually, your plants are a little larger and more robust, and sometimes they’re more rootbound. The same guideline applies to hardening them off for at least 5-7 days before planting them outside.
Like seedlings, give your plants a good soaking the day before or at least a few hours before you plan to plant. Dig your planting hole and then gently ease the plant out of the pot, squeeze around the outside edges to loosen and then tipping upside down while supporting the plant and soil ball with your hand. Try not to pull by the stem. You may need to use a butter knife to loosen around the edges of the soil and cut off any roots hanging out the bottom drainage holes.
If your starter plants are quite rootbound, do your best to untangle them all around the root ball so that they will spread into the soil around them when growing. Suppose they’re extremely root bound, and you can’t separate them with your fingers. In that case, you may need to use a sterile sharp knife to carefully slice an X across the bottom of the root ball and make a few vertical slits in the side of the root ball; this will encourage the roots to spread out instead of staying tight in a ball.
Same as seedlings, fill your planting hole half full with water, then place the plant, firmly pressing down on the surrounding soil. If you are planting into a container and your soil has been well hydrated, you may not need to water immediately. Make sure to give newly transplanted starter plants another thorough watering right after you backfill the hole to eliminate any air pockets in the soil.
Transplanting Shrubs & Trees
Spring is an excellent time to plant a tree or shrub. If you’ve got a new tree or shrub that’s ready to go in the ground, here’s what you need to know to get it planted successfully.
When choosing where to put your tree or shrub, measure out its full mature size. It might look weird for now to have a tiny azalea shrub 4 feet away from the house or sidewalk with nothing else around it, but if that azalea gets to 8 feet tall and 8 feet wide, you’re going to be glad you planted it 4-5 feet away from the house. Mark or measure out the possible mature size of your tree or shrub, and make sure to plant it where it won’t interfere with your house, fence, power lines, sidewalks, or other trees and shrubs.
Once you have decided on an appropriate location, you can start digging. Trees and shrubs need to be planted so that the crown of the root ball is at ground level. So the hole should be about as deep as the pot they came in and 2-3 times wider. Remove your tree or shrub from the pot. You may need to cut the pot to remove it. Once the root ball is out of the pot, loosen some of the roots on the sides and the bottom. Like smaller plants, if the tree or shrub is extremely root bound, you may want to cut some vertical slits and an X across the bottom of the root ball.
Amend the soil with compost, sea soil, or garden soil mix. We suggest you put all of the native soil you dig up into a wheelbarrow and mix your compost/amendment into that. Usually, the formula is ⅓ compost to ⅔ native soil. Once you’ve loosened the roots, you can set the tree or shrub in the hole. Make sure the root ball’s crown is just at the soil line, and then start backfilling.
Fill the planting hole halfway while stabilizing the tree or shrub, and then fill the hole halfway with water to help the lower layers of soil settle in and eliminate air pockets. Once the water soaks in, continue filling the hole until you’ve reached level with the top of the root ball. Firm the soil well with the heel of your shoe, and then apply a mulch over the root area, avoiding the tree trunk as mulch can slowly suffocate the tree when placed too heavily around the trunk.
You can create a berm, of mulch or soil, around the root zone, about 2-3 feet out from the trunk of the tree, to help water stay in that area when you’re watering. Most young trees need staking, so make sure to anchor your trees well to support the tree in case of a storm.
Moving a Small Tree or Shrub
Transplanting a tree or shrub in your yard to a new location is a bit more involved since you also have to dig it up. Small is the critical word in the heading. Moving large trees and shrubs is very difficult and less likely to survive the ordeal. If your tree or shrub is relatively young and small, moving it might be pretty simple and trouble-free.
Before you start digging up a tree or shrub, you should estimate the size of the root ball to make sure you want to take on the challenge of digging up a giant ball of soil and roots that will be very heavy. Think of the phrase, ‘as above, so below’. Is the crown of your tree large? Then the root system likely mimics this size.
The general rule of thumb is that the root ball should be 10-12 inches in diameter per inch of trunk diameter. For example, if the main trunk of your tree or shrub is 3 inches in diameter, you should aim to dig up a root ball approximately 36 inches in diameter.
Before you start digging:
- Choose the new location, and dig the new hole first.
- Make sure you select a site appropriate for the tree or shrubs’ needs for light and water.
- Estimate the size of your root ball, using the guidelines above, and dig the new hole 2-3 times as wide as the estimated root ball.
Exposing the roots of your tree to air can be stressful for the tree, so you want to be able to get it into its new hole and start covering those roots as quickly as possible. Once the hole is ready, you can start digging your tree or shrub out. Start digging about a foot further out from your tree than your estimated diameter, and carefully dig around your tree or shrub. Figure out where the bulk of the roots are, and once you’ve gone all the way around, start digging under the root ball. You’ll need to go quite deep to make sure you get enough roots and avoid damage to the main roots, at least 2 feet deep for small trees and 1.5-2 feet deep for shrubs.
You will probably need to cut through some roots while digging up your tree or shrub; it’s almost unavoidable. Just make sure they’re clean cuts with a sharp spade or knife and keep cuts to a minimum. Once your tree is fully dug up, move it into its new hole and start backfilling as quickly as possible, following the same guidelines as planting a tree from a container. Even if you didn’t stake your tree in the previous location, you should stake it in the new site to stabilize it as it re-establishes itself.
Have you stopped by the garden centre yet to see what’s in store for the spring? Plants are flying out the door, so if you have particular varieties in mind, you should stop in sooner than later to get what you need for the 2021 growing season.