A Guide to Successful Planting
Bare root transplants, roses, trees etc
Bare root trees, roses, etc should be planted as soon as they arrive. If this isn’t possible then please leave the plants in their bags in a cool, frost-free environment out of the wind and sun and as rodent-proof as possible. Keep the roots moist, never allowing them to dry out. In this way, the plants should keep happily for about a week. If planting has to be delayed for more than a week then it is essential you ‘heel’ them in. Bare root plants should be replanted at the same depth they were when growing on the nursery. A soil level mark can usually be seen on the stem which will be of a slightly darker colour than the trunk. This mark should be level with the top of the planting hole but where it is difficult to see, aim to have the graft union about 10cm above ground level.
Try to pick up rootballed plants by the rootball rather than lifting them from the stem as this puts a strain on the roots and can cause the rootball to fall apart. Always place them down carefully rather than dropping them. The hessian root-wrap is usually held in place around the roots with rubber bands and knots. Leave all of this intact when planting as it prevents root damage and will rot down naturally. If any of the knots are seen to be strangling or rubbing against the stem of the tree they can be cut away once planted. Some larger rootballs may also have a wire mesh wrapped around the hessian. This too should be left in place as the roots will happily grow through as the metal gradually breaks down. When planting, position in such a way that the hessian on top of the rootball is just visible above the soil level after backfilling. It is better to plant the tree a little high than to plant it below the original growing level particularly as some settling may occur post planting. For evergreen species such as Taxus and Prunus lusitanica, it is beneficial to have the rootball remain proud after planting (see Hedging below). When planting in grass, leave an 80cm+ circle free of turf for at least the first season and cover with a bark mulch.
Potting on of plants is carried out all year round in order to maintain supply. This may result in some plants being sent out that are not completely rooted through so please take additional care when planting them. Adversely, the opposite may sometimes be found with roots circling the bottom and sides of the pot. In such cases the roots should be carefully teased out. If you are unable to plant straight away then store containerised plants outdoors (unless frost prone) in a cool, light, sheltered spot and water when required. Resist the temptation to store them for a length of time in a greenhouse as this can soften the growth of plants that have been hardened off.
Avoid digging the planting holes before receiving your plants as they may fill with water and/or freeze which will ruin the soil structure. Nor should you plant in frosty weather as roots may freeze in the cold air and frozen soil does not tread in well, causing air pockets to be left around the root zone. It is best to ensure the plants are left in their bags until the last possible moment in order to avoid them drying out in the sun or wind. Be aware when working in clay soil that a planting hole can easily act like a sump and collect water that is unable to drain away. It isn’t sufficient to simply backfill with imported soil or planting compost as allowing the tree to sit in stagnant water will ultimately lead to root death. When planting, the aim should be to provide an area that is at least double the size of the existing rootball. This surrounding zone of improved soil will offer the ideal environment for the roots to grow into, quickly doubling the root mass and allowing the plant to establish strongly. Always ensure that any compost or manure added to the backfill is thoroughly mixed in. A well-developed root system is paramount to a plant’s long-term health and success.
- Hedging (evergreen): We advise that when planting Taxus, Prunus lusitanica and Ilex hedging, you plant with the top of the rootballs slightly proud of the surface so they form a slight ridge. This ensures the roots can still ‘breathe’ in heavier soils and in periods of prolonged wetness. Avoid putting excessive amounts of compost or manure into the planting hole of conifers as they will not appreciate it. Trickle irrigation comes highly recommended as an aid in successfully establishing mature hedging.
- Topiary: Avoid setting box balls as low as possible, as planting them too deep will bring about a slow and needless death. They are sometimes supplied potted for transport purposes and this can give a false impression of the level they were planted on the nursery. A close inspection at the base of the plant will reveal the depth they should be planted at (see Bare root above).
- Roses (potted): The potted roses we supply are potted in late autumn for supply right through to late summer. In the first few months following potting, care should be taken when removing the plants as a lot of the compost will fall away. Treat as a bare root plant when this occurs.
- Climbers: When planting against a wall or fence ensure the planting hole is dug approx 50cm away in order to avoid the dry areas found at the base of these structures. Consider planting Clematis 10cm deeper than they were in the pot to protect them from clematis wilt.
- Perennials: Some growers, in preparing their plants for dispatch, will top-dress the pots with fresh compost or bark chippings. This will often fall away when the plants are removed from their pots and should reveal the true depth at which they should be planted. The rhizomes of Iris germanica (Bearded Iris) require full sun on them to flourish so ensure this is left exposed when planting.
- Rhododendrons: A site with an acidic soil of pH 3.0 – 6.0 is essential unless you have selected lime tolerant varieties. Although a moist soil is preferred, they will not survive in saturated ground so good winter drainage is a must. An ericaceous compost should be incorporated in the backfill but avoid animal manures as they will be too strong. Heavy mulches and weed membranes are not advisable as these plants are surface rooting and require good aeration. A slow release ericaceous fertiliser applied annually in early spring will be of benefit as will dead-heading immediately after flowering.
For larger plants we recommend backfilling the planting hole to about 15cm from the top then water-in thoroughly. This not only limits the amount wasted with run-off but also gives a clearer idea of how much water is required to irrigate in future (ie, more than you think if it drains quickly, less if sits around). Once they have been watered-in, the most critical time for watering is in spring from the point where the buds are about to break. If insufficiently watered at this time the buds may fail to break or may break then just wither and die. Care must also be taken not to over-water as this can easily bring about the same symptoms. There is no real substitute to having a little dig under the soil surface to accurately assess the level of moisture in the root zone. Newly planted trees should be watered regularly during their first season of growth, particularly in dry or windy spells. For a typical 8-10cm girth tree, a couple of watering cans or buckets two or three times a week should be sufficient in all but the most extreme soil and weather conditions. For larger more mature trees, an increased amount of water will be required.
Younger trees, provided they are growing healthily, should develop sufficient new roots in the first growing season to be able to support the tree from then on. It may therefore, be possible to remove the stake at the start of the following season. For mature trees this can take three years or more but it is essential that the stake is removed once the tree can stand unsupported. Trees planted into poor soil conditions are unlikely to become self supporting and staking may be required throughout the tree’s life. The most common problem encountered with staking is with the ties becoming too tight. Ties should be checked regularly for signs of rubbing or constriction and adjusted where necessary.
Composts & Fertilisers
Fertilisers should only be used in addition to thorough soil preparation and should not be seen as an inexpensive or labour-saving alternative. Common problems such as compacted, waterlogged soils need to be remedied before the first bag of compost or fertiliser is opened. Preparing and conditioning the soil is far more important to long-term plant success as it enables easier access to nutrients and allows oxygen and moisture to permeate freely, all of which encourage strong and healthy root and plant development. The addition of organic matter through the various composts and manures available can greatly assist in soil conditioning and will slowly release nutrients into the soil. An application of bone meal or a suitable granular fertiliser mixed into the planting hole may also aid plant establishment as long as the correct dosage rates are followed. Do not apply these directly onto the roots and never apply extra fertiliser just to be on the safe side. Matching your choice of plant to the site conditions is far better than trying to make the site suit your plants!
A mulch of bark or compost can be of great benefit in retaining moisture, suppressing weeds and enhancing the overall appearance. However, care should be taken to leave a little free space around the base of plants as direct contact with the mulch can lead to problems, eg bark on the branches of shrubs and the soft stems of perennials may start to rot and less vigorous plants can struggle to force their way through in the spring.