Planting a well-designed grouping of plants can be a challenging task, especially when dealing with the fast growing trees or shrubs, which increase twice in size in 5 or 10 years. The slow-growing conifers and deciduous trees with an annual growth rate of only 1 to 2 cm, or those which are generally kept in shape by regular clipping, lend themselves far better to such planting schemes.
Several mistakes are commonly made when grouping trees and shrubs – either they are planted too close to each other, or their forms or colors clash, or their have different cultural requirements, or they simply hinder each other. The first consideration in choosing plants is to decide what their purpose is whether they will be planted in groups or as specimen; in the middle of the lawn or at its edge; next to the fence, in front of the house, or in the backyard. Some trees and shrubs look spectacular when arranged in groups, while looking completely unremarkable planted as accent plants. When making a choice for your garden, bear in mind the ultimate form or shape of the trees in their later years. The plants may look well-spaced today, but will this still be the case in 10 years time?
Choose plants not only by their appearance but also with a view to what their cultural requirements are. Some plants are sun-lovers, while others flourish in a light shade; some thrive planted in clay soils, while others prefer a sandy, well-drained spot; certain plants cannot stand any competition whatsoever. When mixing species, it is also worth considering how fast they will grow. If some plants grow at the rate of 15 to 50 cm a year, while others put on a mere 1 or 5 cm of growth during the same period, then the planting will soon loose its proportions, and you will have to resort to moving certain plants.
Try to sketch your design on paper beforehand. Make a couple of drawings – one of the grouping of the trees and the shrubs at planting time, and another one of its expected mature look in some 10 to 15 years. If you are working with potted plants, spend some time arranging them according to your design, and take a picture. It might turn out that you do not like this particular arrangement, so keep on shuffling the pots until you achieve the desired effect.
Usually, plants look best when planted in groups of odd numbers, such as 3, 5 or 7. The most flattering way is to plant them at the edge of the lawn or close to the flower borders, which directs the eye from the ground to the sky. When planting a composition of plants into the middle of the lawn, the trees and the shrubs are arranged by their size and vigor, so that the group looks well from every angle, with the tallest plants in the middle, and the low-growing ones on the sides.
The trees can be arranged in dense or sparse groups, depending on the distance kept between plants. Crowns of plants, grown in dense plantings, will eventually grow into each other. The tall trees and shrubs are often planted in dense groups, with the purpose of creating a backdrop for the surrounding plants. A nice effect can be achieved when associating trees with foliage of complimentary colors, or those which display bright autumn hues.
A tall and dense hedge can serve as a sheltering belt, protecting adjacent plants from wind and scorching sun. The tall and vigorous trees are generally planted in city parks and squares, in the country estates, since they eventually mature to considerable dimensions. A spacing of 4 or 5 mis adequate for the trees in dense plantings, while 2 or 2.5 m are sufficient for the shrubs. The crowns of the trees planted in sparse groups should not block out the view, therefore, an interval of 5 or 6 m between the plants is more appropriate. Such groups are commonly planted at the forefront, or along the paths or the alleys. Small-leaved deciduous trees (e.g. birches, poplars) or conifers with light crowns (e.g. pines, larches) are planted in sparse groupings, while large-leaved trees (maples, ash trees) and thick-crowned conifers (e.g. spruces) make spectacular dense plantings. The larger the ultimate size of the trees planted, the fewer trees should be planted in the group.
Do not forget conifers, when planting a grouping of plants, for they will add plenty of winter interest. Take into account the overall structure of deciduous trees or shrubs, since some of them, such as the sumac trees, are rather attractive in their own way even when leafless. Plants with clear-cut geometrical crowns look better planted as specimen plants or as a part of a mixed border. The group of trees and shrubs should look comfortable in their surroundings, with a pleasing overall outline.
Plants of the single species can be planted as specimen plants; however, they look best when planted in groups of several. Trees and tall shrubs are often planted in threes, while medium-sized and small shrubs look best planted in groups of threes or fives. Where space is limited, the trees and the shrubs are usually interspersed with flowering perennials. In a typical English garden planting scheme, perennials are planted very densely so that they cover the soil completely, meshing in time into a colorful and glorious flowering carpet.
© Giedra Bartas, 2009