With the increasing interest in low maintenance gardening, shrubs provide an ideal medium to achieve this and create beautiful effects. Their diversity in providing flowers for every season, fruits and berries in winter glorious shades of leaf color during autumn means no garden should ever be without color and interest.
By carefully planning a garden it is possible to combine the aesthetic beauty of plants and utilize their natural covering habit to reduce maintenance cost. Obviously the bigger the garden the more important it is to keep these costs to a minimum.
Planning the Border
Where new shrub borders are intended, it is advisable to prepare a simple plan detailing exactly what is to be planted where it will look effective, and with what it will combine well. Obvious considerations must be the ultimate height and spread of plants being used.
There are many permutations one can try with plants, possibly use of contrasting foliage, shapes, size or simple color combinations using flowers or foliage. Above all avoid ‘bitty’ planting, using single plants dotted at random over the garden. Nothing looks more unattractive and completely disjointed. Try where possible to plant in groups however small—threes or fives can look very effective and produce a bolder massed effect.
A point worth remembering is to select subjects which will provide interest in the border throughout the year. With such a variety of plants on the market this should not be difficult. Prior to planting, set plants out in their positions and assess whether anything looks drastically out of place.
The basic principles are similar to those outlined for trees, differing mainly in size of root system. This does not mean shrubs can be squeezed into tiny holes. They must be wide and deep enough adequately to accommodate the root system, thus allowing space for new root development. If the plants, particularly bare rooted types have been standing around for some time, ensure they are well soaked before planting. It is advisable to cut away any hessian or root wrap as this may well restrict root growth if left.
Container grown plants cannot be left in pots unless they are of the degradable type. If in any doubt remove them just prior to planting. Always aim to plant shrubs at the precise depth at which they have previously been grown, checking the depth of the hole before backfilling with soil. If possible, plant when soils are moist and the sky overcast—not terribly difficult conditions, especially if you live in Britain or certain states in North America.
Try to keep to your planned spacing as this should ensure each shrub has room to develop, accepting that in 4-5 years it may require judicious pruning to keep them in bounds. By astute selection and spacing, it should not be many years before shrubs begin to repay costs by effectively covering the ground thus reducing need for regular weeding and maintenance. When the planting operation is finished water everything thoroughly, lightly fork out foot marks leaving the border neat and tidy.
A top dressing or mulch of well rotted compost or peat is always beneficial as it provides plants with extra food, prevents loss of moisture at the root, cools the soil and restricts weed growth. In general, little in the way of maintenance except to keep them weed-free until they are able to spread naturally and suppress weeds themselves.
Not all shrubs benefit from regular pruning. There are several vital points one needs to know before attempting to prune. Firstly a knowledge of when the plant flowers, what type or age of wood it flowers on, and finally how much if any wood can be safely removed without spoiling the plant.
The time of flowering and type of wood obviously governs when and how much to cut without fear of losing flowers. Shrubs like camellia, hamamelis and daphne resent having much, if any wood removed, and are therefore best left unpruned. The periodic removal of all dead, diseased, or dying wood does much to improve the general health of shrub by allowing freer air movement within the plant.
Of the shrubs that require annual pruning we can roughly divide these into two groups. Those flowering on new wood produced in the same season like Buddleia, Caryopteris, and certain Spiraeas, are best cut back to a framework in March with the complete removal of all finished flowering shoots.
The new shoots which emerge provide flowers later on in the season. Failure to prune these types annually results in fewer, smaller flowers. Another group of shrubs responding to cutting hard to within 5cm/2in of ground level each year are those grown specifically for winter stem color.
Most of the shrubby willows Salix spp and many Cornus benefit from ‘stooling’ each spring. Never attempt to prune until after winter when maximum stem effect is seen. The second major group is shrubs which flower on wood produced in previous seasons on two or three year old plants.
Within this group are spring and summer flowering types, but both require pruning as soon after flowering as possible. Here the majority of younger flowering shoots are cut back by half, and any old woody basal growth must be removed to encourage new breaks from below. Any growth produced in the later half of the season forms the basis for flower in the following year.
Of the spring flowering types Forsythia, Abeliophyllum, and Ribes are pruned as flowers fade while Philadelphus Mock orange, Weigela, and Deutzia represent the summer flowering plants.
Evergreens rarely require much in the way of extensive pruning. Perhaps the odd shaping from time to time, and occasionally when a specimen outgrows its situation drastic steps may have to be taken. Here overgrown evergreens can be cut back to within 3cm/1in of ground level just before growth commences around April or May.
Certain evergreen such as Prunus and Rhododendrons respond to this treatment, however it must only be practiced as a last resort to keep plants to given areas. When pruning or cutting any of the larger leaved types it is wise to use hand pruners, not shears which may damage leaf tissue.
A vitally important aspect of pruning is the use of sharp tools, generally hand pruners or knives. Blunt or damaged implements may result in bruising or damage to stems of shrubs. This often leads to slower healing of cuts thus allowing more time for disease to colonize any exposed untreated areas.
Good clean cuts always heal far quicker than dirty, damaged, cuts. Always ensure that pruning tools are the correct type for the job. Never force small hand pruners trying to cut a thick shoot. If it is too large choose something more suitable like a small hand pruning saw. When making a cut on a shoot try to leave at least 1cm or ½ inch above the bud, with a slight slope angled away from the bud to permit water runoff.
Finally any cuts made into wood of more than 1cm or ½ inch diameter must be treated with a fungicidal tree paint sealant to protect the shrub from infection.
Shrubs for Year-Round Display
Winter Sweet (Chimonanthus praecox) Deciduous shrub to 3m/10ft. FIs waxy yellow, stained purple, highly scented. Prefers a sunny position to ripen wood, will tolerate most soils including chalk.
Witch Hazel (Hamamelis)
A beautiful group of slow growing deciduous shrubs. Grows well in any fertile soil in a sunny or partially shaded position. FIowers mainly yellow, some orange through to red from November to March.
A delightfully scented very hardy deciduous shrub to 2.4m/8ft. Free flowering in any open well drained position. Pink in bud opening white November—February.
Spring Flower Camellia
A large group of very attractive evergreens with dark green shiny Ieaves. Best grown in a semi-shaded situation. Many fine cultivars of Camellia japonica can be found. C.j. ‘Adolphe Audusson’ has large semi-double deep red flowers. Perhaps most popular of all C. williamsii ‘Donation’ a delicate free flowering double pink type.
A group of neat compact sweetly scented spring flowering shrubs. D.burkwoodii is one of the best and longest lived with pale mauve-pink flowers in May. D. mezereum-deciduous flowers February-March, scented, reddish-purple before leaves appear.
Star Magnolia (Magnolia stellata)
One of the many beautiful Magnolias forming a dense low branchwork. Ideal for small gardens as it rarely exceeds 3m/10ft. Flowers white with strap-shaped petals very profuse March-April. Prone to spring frost damage. Prefers a sunny situation on most reasonable soils.
Mexican Orange Blossom (Choisya ternata)
A neat round shaped evergreen shrub to 1.5m/5ft. Flowers white highly scented May-June. Prefers a sunny fairly sheltered position on a good loam soil.
A good ground covering type requiring an open sunny situation, forming dense compact bushes covered in golden yellow flowers from mid-summer to autumn. Many cultivars seen with flowers from yellow, white, orange and the very recent P. ‘Red Ace’ with dark red flowers. Tolerant of any good well drained soil.
Mock Orange (Philadelphus coronarius)
A common name referring to the remarkable likeness of the flower scent to the Citrus. All very hardy, easily grown, tolerating acid or alkaline in sunny position. Flowers June-July scented, yellowish white.
Smoke Bush (Cotinus coggygria A slow growing very decorative deciduous shrub to 3m/10ft. Common name from hazy look of persistent dead flower heads. Leaves turn remarkable shades of deep crimson and red in autumn. Prefers a well drained soil in a sunny position.
A slow growing deciduous shrub related to witch hazel with spikes of feathery white flowers appearing April, May. Leaves like hazel turning spectacular shades of yellows, golds, and orange in autumn. Requires a neutral or lime free soil.
One of the best of all deciduous shrubs for richness in autumn color. Slow growing deciduous low-spreading shrub to 1.2m/4ft having curious corky wings on shoots. Most soils even shallow chalk.