In addition to color and plant shape, use texture to increase the aesthetic appeal of your plantings. Texture describes the surface quality of an object that can be seen or felt. When designing plantings, it is this visual texture (as opposed to the tactile experience) that we are most concerned about.
Plant textures range from fine to medium to coarse. (Coarse is often called bold.) Most plants are medium textured. But using fine- and coarse-textured plants purposefully adds interest to plantings.
Fine-textured plants usually have small leaves and/or blossoms. They have a light and airy feel and create an illusion of filling space. They are relaxed and undemanding, and tend to recede into the background. They can make small spaces seem bigger. Fine textures accentuate the form and color of other plants. Think baby's breath.
Other common fine-textured plants include honey locust, asparagus, lavendar, maidenhair fern, love-in-a-mist, dill, fennel, wild bleeding heart, albizzia, tarragon, spirea, yew, and Japanese barberry.
Coarse-textured plants usually have large leaves and/or blossoms. They are exciting, in-your-face attention grabbers. They give a garden a heavy, tropical feel. Used in masses, they make spaces feel smaller. Coarse textures compete for visual attention with the form and color of other plants. Think hostas. (Particularly the uniformly colored, large-leaved cultivars.)
Other common coarse-textured plants include rhubarb, comfrey, catalpa, Dutchman's pipe, many rhododendrons, castor beans, bugloss, bananas, saucer magnolia, and cannas.
Texture is actually determined by light and shadow. Fine-textured plants reflect many small patches of light and shadow. Coarse-textured plants reflect fewer, larger blotches. You could paint a picture of coarse-textured plants with a broad brush, while fine-textured plants would require a delicate one.
How we view texture also depends on distance. Up close, most needle-leaved trees have a very fine texture. But step back to the other side of the yard and all those needles coalesce into a coarsely textured form.
The plant's branching habit also affects its texture. Small-leaved plants that have a tight and twiggy branching habit (such as Japanese yew and Japanese barberry) produce a dense effect, making the plant look more solid than it really is. Other small-leaved plants that have an open branching habit (such as abelia, honey locust, and royal fern) provide a light and airy feel.
Textures can vary through the season. In winter, the bark and branches of woody plants become the dominant texture-providers. Leafless shrubs with many slender twigs have a fine texture. Shrubs with fewer, stouter stems appear coarse- or medium-textured.
In early spring when there is little foliage, bulb blossoms may set the texture tone. But in summer, texture is largely determined by foliage.
Beyond leaf size, many other characteristics affect the overall textural impression of a plant. All other things being equal, each of the following contribute to giving a plant finer texture:
Compound, dissected, or lobed leaves.
Contrasting light underside of leaves.
Ridged or shiny leaves.
Regular placement of leaves along the branch or stem.
Flower or fruit breaking up the regular pattern of leaves.
Motion also contributes to a finer texture when wind causes the patterns of light and shade to constantly change. Plants with leaves with long, flexible petioles and ornamental grasses that sway in the breeze provide a finer texture in motion than they do at rest.
A planting with all medium-textured plants can feel lackluster. Still, adding too much textural contrast can make a garden feel busy. If fine-textured plants dominate, a planting can lack focus without some specimen plants to catch your eye.
On the other hand, too many coarse-textured plants can look awkward and unwieldy. They do not look as bold without some medium- or fine-textured plants for contrast.
Finally, as with color, there is no right or wrong with texture. Just being aware of this quality can help you design plantings that are more pleasing.