As with all plants, you can plant bare-root stock during the dormant winter period, weather permitting, and containerized plants all the year round, again providing the weather is suitable — do not plant during conditions of water-logging, frost or drought.
The same method is used as for any other garden plant – well dug and prepared soil, plenty of rotted organic matter, and planting holes large enough to take the root or root ball without trouble. If you are planting in the spring and summer, you can use growmore or other quick-acting fertilizer as a top-dressing, bone-meal being more suitable for autumn and early winter. Always make sure that the new soil line is at the same height as the old one on the stems or trunks in the case of bare-root and root-balled stock. If it has been grown in pots or other containers, the tree, shrub or conifer should be planted no deeper than for the soil just to cover the compost round the roots.
Always plant trees, shrubs and conifers firmly, and if there is any chance of the wind rocking the plant before it is established, support it with a strong cane or canes, or a stake, otherwise it will probably die. All young trees, unless they are very small, need a strong stake (about 2 X 2 in., 50 mm sq.) preferably of hardwood, but treated softwood (not with creosote) will do. This should be long enough to support the head of the tree. Knock it well down into the prepared hole first, then put the tree against it and spread the roots out around it, before you backfill the hole. Secure the tree to the stake with one or more proprietary tree ties, making sure that no part of the trunk or any branches are rubbing against the stake before anchoring it finally. Mulch the tidied up, newly planted shrubbery to conserve moisture.
What about the container? One of the aspects of planting new stock which seems to worry inexperienced gardeners more than anything else is – what do you do about the container or other root wrapping that bought plants frequently come in these days?
Polythene containers, plastic solid or open pots and plastic netting will not rot and must always be removed. Some nurseries use an automatic root-baller which encloses the bare roots in peat or compost held in place with a kind of elastic net. You will often find that the roots inside are bunched and constricted, so this also should be cut off and the roots properly spread out.
Pots made of treated cardboard, peat or other consolidated organic materials will eventually rot, if they are well soaked before planting. However, it is sometimes difficult for the novice to identify these, so, if in doubt, unless there are actual signs of the roots growing through the sides of the pot, the container should be removed.
Hessian sacking was once used a lot for root-balling but has now largely been superseded by non-rotting, man-made materials. If you are sure it is real hessian, the whole rootball can be wetted and planted intact, but if you are not certain, the best thing is to place the plant in the hole in its final position, then loosen the sacking from the stem with a sharp knife. It will fall away, but the ball should remain intact long enough for you to fill up the hole without disturbing the roots.