Incorporate extra grit if your soil is poorly drained or if your plants require it – this is particularly important if you’re planting bulbs and alpines.
Add organic matter to improve the soil. High levels of organic matter are required by some plants but all will benefit.
Level off the site and break down large lumps of soil.
If you have not prepared the whole area dig a hole for the plant twice as wide and as deep as the original container and improve the soil as above. If the soil is low in nutrients – for example if your soil is sandy – add a light dressing of fertiliser in the planting hole and mix well. Add a further light top dressing after planting but not close to the stem. Do not use large amounts of fertiliser as this can damage plant roots.
Check the hole is large enough for the plant, ensuring all the roots will fit in when extended.
Soak the plant. Immersion for a short time is the best method – when bubbles stop coming to the surface, remove and allow the surplus water to drain away.
Remove the container and if the plant roots are dense gently loosen so they will branch out into new ground. Ideally, new roots will just be reaching the outside of the pot at planting time – in this case do not disturb at all.
Depth of planting is important: the plant should usually end up at the same depth in the ground as it was in the pot. Place a pole across the planting hole to enable you to judge this.
Planting depth can be important with some plants – for example plant peonies too deep and they will take years to come into flower. Plant clematis too shallow (the lower stem should be buried) and they are susceptible to clematis wilt. Check plant instructions for details on planting depth.
Water in well, thoroughly soaking the soil. For trees and shrubs, mound soil around the perimeter of the planting hole to retain water and fill a number of times and daily thereafter for a few weeks. Trees and shrubs may need watering for up to a year. Tall trees may require staking – particularly in a windy site.
Finish off by mulching the ground with a 50 – 75mm (2 – 3in) layer of organic matter to discourage weeds and retain moisture. If you do not, you must scrupulously remove weeds. New weed seeds will germinate quickly, competing with your plants for water and food.
If the roots have been damaged (eg if you have moved the plant from another situation) balance the roots and the top of the plant by pruning. This will encourage the plant to grow away better. Many plants (never rhododendrons) benefit from pruning at planting time. See Pruning Tips for more information about this.
Tip: For alpines and plants susceptible to neck rots, mulch with grit immediately around the stems to keep dry.