Lockdown landscapes part 2: Transplanting and dividing
Updated: Jul 20
We’re fast approaching the time of year when we’d normally be looking to plant new trees, shrubs and perennials. Because we aren’t able to purchase new stock from the nursery, we can still make some changes to our planting schemes with what we already have by transplanting and dividing.
Do you have a small tree, shrub or plant which you enjoy but is just in the wrong location? It’s not too early to get this done, or at least begin the process.
If you have inherited a garden and the planting needs spacing out, consolidating or reorganising, start by selecting the plants which you want to move and assessing their suitability to be transplanted. If you are a novice transplanter, the easiest plants to start with are herbaceous perennials (small non-shrubby plants which flower annually). But be aware, at this time of year (early Autumn) even these plants may need regular watering after moving, so make sure you have a suitable water source and can stay within your councils water restrictions if you are on town supplies. Deciduous small shrubs and trees can also be moved with relative ease (especially if they have already begun leaf-fall) – but evergreen shrubs and trees will require more aftercare.
Start with pruning – pruning your shrub or perennial is necessary before transplanting. This gives the plant less foliage to support during its transition. For larger evergreens it pays to prune off a third of foliage or more and leave a week before digging. Transplanting can be very stressful for plants, by reducing the size of the plant and the amount of foliage, this will help to balance with the roots lost when digging out. It is best if the soil is moist (not wet), it will hold together better when you are digging out the root ball, so you may need to lightly water before digging.
Right: Heavy pruning of a climbing Rose, note the size of plant in the next photo prior to digging out.
You are ready to dig out your perennial or shrub. You will need to know where you would like your plant to be positioned. Dig out a larger hole than you think you might need as it’s best to give the root ball some extra room. We want to imagine a circle on the ground around the plant using the perimeter of the foliage as a rough guide and do your best to dig out as much of that area as possible. You probably won’t have to dig too deep, most plants as well as shrubs and small trees will have most of their roots in the top 30cm of soil. You want to aim to keep as much soil attached to the roots as possible. This is because the fine roots are the ones that draw up the water for the plant most effectively. With smaller perennials this process can be achieved a lot easier - squaring off around the plant with your spade and lifting. Have your transport ready - whether that be a bucket, a wheelbarrow or a tarpaulin. Place your plant in position in the hole, stand back and look at the shape - how is it looking? It may need straightening up or turning before you back fill and firm it in. The soil you dug out can be used to fill around the root ball mixing any organic fertiliser you may have to your backfill will be beneficial. Shrubs and trees might need staking in order to stop them from blowing over.
Left: Digging out the Rose after pruning to a smaller size.
Take care of your plant – Watering is very important at this stage; you would have lost a lot of root mass, and for those larger shrubs (especially for evergreens) they still have foliage to support. You want to make sure you are regularly watering. Every two or three days after your first good water when you have completed transplanting. Perennials and deciduous shrubs are probably not far from losing their foliage now and going dormant for the winter they can be a bit more tolerant of just being left to the cooler days and getting water when it rains at this time of the year.
Division of perennials and grasses almost goes hand in hand with transplanting. More often than not you may find a plant that has just got too large for the space and no amount of pruning will rein it in. If the plant is suitable for dividing, then this is great! It means the plant you have is very happy and if you have a happy plant, you’ll want to reuse throughout your garden. Dividing plants is a form of propagation and is an excellent way to make the most of the plants you have available to you. It not only saves you money but will help to create continuity in your garden, by repeat planting.
Why not start a new garden? Or spread out plants to cover a larger area. Have a wander around your garden, see if it is possible to split up a few different plants to make a new garden bed or brighten up an area that has lacked care and attention. Grasses and Flaxes are a great start to get your confidence up if you have not spilt plants before. Perennials can be the tricky to divide, making sure you get equal parts of the root system.
You may need to do some research to see if the plants you have are suitable for dividing. Once you get the hang of it, it will be more obvious which plants can be split, and how many times. Once you have picked the plants to divide you need to use the same principles from transplanting when digging the plant out. Once out of the ground, have a close look at the base of the plant and work out where you want to split it. As an example, you may have Hosta or Winter Rose (Hellebore) - the technique is to place a sharp spade roughly in the centre of the plant, put weight onto the spade and focus on to getting a clean cut. Your other option is to use an old bread knife. At this point you should have two fairly equal parts. If you are struggling to get the spade through the top, I have found that coming in from the side can be easier. If the two plants are still larger than you would prefer you can continue to divide. Generally getting four plants from one mature plant is typical. See photos of my Renga Renga Lily, divided to a good size and root mass that gives the plant a good chance of survival.
Right: Cutting a Renga Renga Lily in half with a spade, it may seem brutal!
Above: Placing out divided plants before planting.
Some plants can have very little root system and survive very well. Before placing in the prepared hole, you may need to remove some of the foliage to reduce the loss of water through the leaves. There may be some casualties, especially if you have divided a plant multiple times. Don’t be disheartened, if you come out with one extra plant, that’s still a success!
Aftercare of your divided plants is very important. You have halved maybe even quartered your plant, so watering the roots is very important. Mulching around you new plants will help protect them over the winter months and hold in the moisture whilst supressing weeds.
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