How To Grow Conifers

Yew topiary with tulips and white forget-me-nots at Levens Hall, Cumbria

Follow our hints and tips for success growing conifers

Planting

• Make sure you have the right variety in the right location.
• Don’t plant where they will be subject to strong cold winds as they will burn and go brown.
• Most conifers like an acid soil so incorporate some ericaceous compost into the planting hole.
• Dig a hole to accommodate the size of the pot and loosen the soil around the sides with a fork; this allows the roots to penetrate easier.
• Tease out the roots if planting a containerised conifer as they may be circling the pot and will continue to do so when planted in the ground.
• Plant to the same depth as it is in the pot.
• If planting in a container, choose a container at least 3 times the size of the pot it is already in. Make sure it has plenty of drainage holes; cover them with a piece of crock to prevent them from blocking with silt. Plant in ericaceous compost.

Aftercare

• If you have planted a Leylandii hedge make sure you keep it under control and it will make a lovely thick, crisp clean barrier. If you want the hedge to be 180cm (6’) high let it grow to a height of 210cm (7’) then cut it back to 180cm. When cutting the sides taper them in to the top otherwise the bottom doesn’t receive enough sunlight which can sometimes lead to brown patches.
• Feed in spring with a dedicated fertiliser for conifers, water in then mulch with ericaceous compost or composted pine needles.
• Water well for at least 18 months after planting until the roots become established and can seek out their own water.
• Conifers in containers may have to be watered twice a day if the weather is really hot.

Cloud pruned hedge

Problems

• Conifers most commonly suffer from brown patches which can be caused by a number of factors; aphids or fungal diseases, but the most common cause is adverse growing conditions. This can be that the soil is too waterlogged or too dry, a prolonged period of frost or a cold north or east wind.
• Often the first sign of an aphid attack is the presence of sooty mould so you may have to either spray the mould with a fungicide or soapy water before spraying the insects with an insecticide, as this could prevent the treatment from penetrating the plant. Only spray with an insecticide if you can actually see the insects as sometimes by the time their presence is evident they have moved on.  
• If the tree dies completely honey fungus or Phytophthora could be the culprit in which case the tree needs to be removed and destroyed. Don’t plant another conifer or vulnerable species in the same spot.
• Don’t cut back into old wood as conifers don’t regenerate. Just give them a trim in April, June or August.
• If the brown patch is extensive it can take many years, if at all, to regenerate so removing the tree could be the best option. If there is just a small patch you may be able to tie a healthy branch over it.  

Yew topiary at Levens Hall

Varieties

• A good rule to remember is if you want something fast growing it won’t stop until it reaches a substantial height. If you opt for a slow growing variety it will take a long, long time to reach its ultimate height. Conifers don't grow fast then suddenly stop at a reasonable height.
• Be wary about planting conifers in rockeries as they can often become too large and removing them will almost inevitably involve removing the stones.
• Cloud pruned conifers give a sculptural element to the garden and are ideal for a Japanese garden. Other varieties for a minimalist style garden are the Pinus thunbergii (Japanese Black Pine) which can eventually reach 30m (98’), so not one for a small garden; Pinus mugo (Dwarf Mountain Pine) and Cedrus deodora (Weeping Green Ceder).
• If you want to have a go at cloud pruning yourself try the Cryptomeria elegans aurea which reaches a height of 210 – 270cm (7 – 9’).
• Keep your conifer small by growing in a container.
• Pinus wallichiana (Himalayan Bhutan Pine) produces fantastic long cones, ideal for Christmas decorations, is very slow growing and can be kept in check by pruning.
• If you need to cover a problem steep slope Juniperus communis ‘Green Carpet’ is ideal.
• Try a parterre hedge of Taxus baccata (Yew) then you won’t have the problem of box blight; it also grows quicker than you think.

If you would like any help with any aspect of gardening just get in touch with our Outdoor Plant team here in store.