Care of Shrubs and Ornamentals
The term ‘shrub’ is not a strict biological term; it describes small to medium-sized woody bushes. Shrubs have woody stems but are distinguished from trees by their multiple stems and generally shorter height. Some plant species will grow into either a shrub or a tree depending on the conditions.
Shrubs tend to be used to provide, shape, colour, texture, shelter and backgrounds in gardens. Shrubs come in many shapes, sizes, colours and forms. There will be many options for you to choose from when selecting shrubs for your garden.
Shrubs are generally low maintenance plants requiring little care but they may need some care such as shaping, soil enhancement, and protection from weather, pests and diseases. Hedging and topiary shrubs are a special case as they will be pruned and shaped regularly.
Here are some tips for selecting and caring for your shrubs:
- Advice - Always buy your shrubs from a reputable source so that you are sure they are pest and disease-free. Good growers will have the knowledge to advise you on the best shrubs for your purpose.
- Size and Space - Assess the space you have for your shrub. Choose a variety that will not grow too big and will be an attractive feature or background plant when half to fully grown.
If you are going to grow the shrub in a container it can be moved to situations that suit its size as it grows.
- Shape – Consider the shape of the shrub; shrubs will have the general natural shapes:
- Round – semi-sphere to spherical
- Pyramidal – cone-shaped
- Spreading – wider that tall
- Weeping – leaves or branched falling downwards towards outside of the shrub
- Columnar – taller than wide
- or narrowly columnar – much taller than wide (pencil-shaped)
- Texture - Combining shapes, sizes and colour can give an architectural feel to your garden.
- Colour – There are some factors to consider when thinking of the colour of your shrub; foliage colour, flower colour and fruit colour (if it bears fruit) and is it deciduous or evergreen.
If your shrub/s are to be the background to other plants, say as the backdrop in a border, choose colours that will be complimentary and give contrast to the flowers in the border.
Think also about any changes in the foliage colours through the seasons or any flowering and fruit/berries the shrub may get.
- Planting – Most shrubs enjoy well-drained sandy soil of moderate fertility. Check before choosing a shrub that it will be suitable for your soil type (texture, drainage and pH) and that it will survive the climate in your area; ask your supplier or check the label.
Add Gro-Sure Planting Magic to the hole and back-fill soil when planting shrubs.
- Keep Clear – Keep the soil around the roots of your shrub clear of grass and weeds so that you can easily water the shrub and add fertiliser.
- Containers – When planting shrubs in containers choose a container approximately 15 cm wider than that in which the shrub is purchased from the nursery or garden centre. Re-pot the shrubs every two years until they are fully grown.
- Light – There are shrubs suitable for all light conditions; full sun, partial shade, dappled shade and full shade.
- Shelter – Shrubs are generally tolerant of frost and wind and can be used to provide shelter to other plants but there are more delicate shrubs that will benefit from a shelter, perhaps from other shrubs. Planting shrubs in groups will provide mutual shelter.
- Watering - For most shrubs, the soil surface should be allowed to dry out before watering. Smaller shrubs with smaller root systems will be less tolerant of the draft so take care to water in hot summer weather. This is particularly true of shrubs in containers. They will prefer thorough water infrequently to a little water often.
- Fertilizing – In good soil most shrubs do not require the addition of much fertiliser. But for flowering and fruiting shrubs add an appropriate shrub fertiliser once every six to eight weeks during the growing season.
Hedging shrubs are an exception because they are trimmed and pruned regularly. Learn more on fertilising Buxus and other hedging.
- Mulching - Apply a mulch of bulky organic matter such as well-rotted manure, garden compost or straw, in mid-to-late spring and autumn. This conserves moisture and reduces competition from weeds and grass.
Spread the mulch about 10 cm deep around the base of the shrub to cover the root ball. Keep the mulch 10 cm from the base of the trunk to prevent the bark decaying. You may also need to prune out the lowest branches so they are not sitting in the mulch.
- Frost Protection - Consider protecting smaller shrubs if frosty weather is predicted because they may be more susceptible to frost damage. See Preventing Winter Damage to Plants.
- Pruning - Pruning shrubs at the correct spacing to allow air and light in encourages production fresh new growth. Hard pruning is best done during winter dormancy; just before new growth begins in spring. Deciduous shrubs that flower in late winter, spring and early summer need annual pruning to encourage strong, healthy shoots and improve flowering. Summer pruning may be necessary to remove undesirable growth and maintain smaller shrub size and shape. Cut back shrubs grown primarily for their foliage anytime except in late autumn. Note, new growth after late-autumn pruning may not have time to harden off properly before winter.
- Pests and Disease – Some shrubs are susceptible to pests and diseases. Prevention is better than cure. Spraying to prevent pests and diseases is usually needed, however, for some susceptible shrubs pro-active protection is advisable to ensure healthy growth. Just a few well-timed applications of fungicide and/or insecticide (see Kiwicare PLANThealth Range) will prevent most problems.
Young shrubs are often more susceptible to pests and diseases, older more established shrubs become more able to resist the pests and diseases.
If you observe the shrub looking unhealthy or damage from pests or disease, identify the problem using the Kiwicare Problem Solver and find the solution.