Common reasons new trees or shrubs fail
It would be wonderful if every new plant we bought thrived. However, as every experienced gardener knows, sometimes new plants do sadly die. Buying from a reputable nursery that offers a 3-5 year guarantee is some safeguard but it is useful to know why a tree or shrub might have died.
Some of the reasons new plants fail can be specific to whether the plant stayed in its pot or was planted into the garden. Other causes of failure are more general.
Plants in the ground
The first two growing seasons after planting are a critical time for a tree or shrub. Unless it gets its roots successfully established into the surrounding soil, it will be prone to failure particularly in times of stress such as during drought or waterlogging.
Establishment failure. Plants that die within the first year after planting are most likely to have failed to establish. Their roots will most likely be dead or stunted. When digging the plant out look for signs of;
- Too wet - wet season, wet soil or overwatering. Remedy: Check the soil around new plants for standing water or waterlogged conditions. Reduce watering where necessary (remember plants in the ground do not need to be watered as frequently as those in containers). Choose plants suited to wet soil conditions
- Too dry - dry season, dry/unimproved soil or erratic/insufficient watering. Remedy: Thoroughly wet the rootball on planting; if the compost or soil repels rather than absorbs the water, add a few drops of washing-up liquid into the watering can to act as a wetting agent. In the first growing season check all new plants weekly for signs of drying, especially in dry weather. Water thoroughly (applying sufficient to wet the full depth of rootball) at the first signs of the soil drying. Choose plants suited to dry soil conditions
- Planted too deep - causes rotting of stem base; a common failure of woody plants. Remedy: Avoid deep planting by positioning the tree or shrub with the first flare of roots (thicker roots, not the fine adventitious roots) just below the soil line. Scrape away the soil or mulch from the base of trees and shrubs suspected of deep planting
- Undeveloped roots that have failed to grow out into the surrounding soil – caused by compacted rootball that was not trimmed or loosened (‘teased out’) on planting, a restrictive root wrapping material or compacted surrounding soil. Remedy: Trim potbound rootballs prior to planting to encourage lateral root growth. Remove root wrappings unless stated otherwise by the nursery. Plant trees and shrubs using good techniques (i.e. dig out a hole one times the depth and three times the width of the rootball) to ensure soil compaction is alleviated. In post-planting cases of suspected soil compaction, carefully loosen a ring of soil to the outer edge of the rootball using a border fork. Congested roots can be trimmed in the dormant season or spring
- Large specimen tree or shrub - these can be more prone to failure than smaller plants, due to an imbalance in the size of the root system with the top growth. Remedy: Only plant larger specimens when there is a special requirement, such as for instant screening, and ensure they are kept well watered for several seasons after planting
Unsuited to site conditions. Some plants are not too fussy about their environment but others will suffer if given the wrong conditions. A plant in the wrong place can quickly fail. Remedy: Check before planting the preferred soil texture (well-drained, moist, etc), pH and degree of sun or shade for your tree or shrub and site it accordingly.
Rabbit, deer or rodent damage. Plants in the ground can get nibbled by wild animals. Although rabbits and deer are mostly troublesome in rural and semi-rural gardens, mice and voles can be found in all gardens. Look for patches of stripped bark on the lower sections of woody plants, especially in winter and the sudden disappearance of stems and foliage of herbaceous plants, usually in spring and summer. Remedy: Where rabbits or deer are likely to be a problem, fit all newly planted trees and shrubs with spiral guards, enclose individual plants or beds in chicken wire or choose plants that are more resistant to damage; check all new plants for mice and vole damage and clear away cover where possible.
Plants in containers
There is no inherent reason why a tree or a shrub kept in its pot should fail – after all, nurseries grow thousands of plants successfully in pots, repotting as required, sometimes for several years before offering them for sale. However, a plant in a container can be more at risk of certain problems that, if gone unnoticed, can lead to the loss of the plant;
- Too wet – wet season/overwatering. Remedy: Bring containers into the lee of a wall if the weather is very wet and check the drainage holes are not blocked. Water when the top of the compost starts to show signs of drying, not before. Plants need less water in winter, if growth is slow, if they are not in leaf or if they are in a large container in comparison to the size of plant
- Too dry – erratic/insufficient watering. Remedy: Check plants regularly for drying out and water if the compost feels dry and/or the pot has become lighter in weight. Plants outside in summer should be checked at least once a day
- Overpotted – plants that are potted into too large a container, especially late in the growing season or in winter can rot off. Remedy: Only repot into the next size pot or downsize plants already overpotted
- Frosted roots – roots can be more vulnerable to cold damage than the top growth so trees and shrubs in containers are less protected from frost than those insulated by the soil. Remedy: Wrap the sides of outdoor containerised plants with bubblewrap before winter and bring them to a more protected position such as us against a house wall
- Vine weevil – creamy-white, c-shaped grubs of vine weevil can wreak havoc with plants in pots by eating their roots. Remedy: Check rootballs at the first sign of a problem and treat if grubs are found. Nematodes are effective for trees and shrubs in the ground
Wind, sun or cold damage
Plants that have changed environment suddenly – for example, from a polytunnel in the nursery to your garden – can suffer from physical damage, being scorched by wind, sun or cold.
Remedy: Unless you know where the plant was growing before purchasing it, harden off new plants by keeping them for a few days in a sheltered/shady spot outdoors under horticultural fleece. Remove the fleece at night but replace during the day for a further couple of days before planting out.
All plants have their limits and may be caught by extremes of weather.
Remedy: Check the growing conditions of your plant to see if it requires protection from wind, sun or cold and position or protect it as required. Fortunately, many trees and shrubs often recover from weather damage, especially if only the exposed side(s) is damaged so cut the damaged parts out and wait until the growing season to give it the benefit of the doubt.
Weak or unhealthy plant
Of course, if the plant you bought was weak or sick at the start, it is highly likely that it will continue to suffer or die in your garden.
Remedy: Inspect all new plants for signs of disease or poor health before buying. Avoid buying sickly specimens. Plants that arrive in a poor state via mail order should be returned or the supplier informed.