Careful planning is required to create an attractive ornamental garden. First, think about the climate. Always select plants suitable for your environment or create a microclimate for them. The main climatic variables for the ornamental garden are temperature, water and light, with one extreme being hot, dry and sunny and the other being cool, damp and shady. Hostas will not thrive on a dry bank in full sun, while delphiniums produce few flowers in shady conditions. Gazanias, geraniums, wallflowers and stocks prefer warm, sunny spots, while begonias, lobelia, polyanthus, pansy and viola do best where the soil is moist and there is some shade. Frost is another factor that will influence the plants you select or where they are positioned. Plants may be described as half hardy (can withstand temperatures down to 0°C), frost hardy (can withstand temperatures down to -5°C) and fully hardy (can withstand temperatures down to -15°C). Some plants have brittle stems and cannot withstand strong winds, while other plants are very susceptible to the salt-laden air of the seaside.
Seasonal changes are another aspect of planning the ornamental garden. Ensure that there are interesting things to look at all year round. Annuals provide great displays in spring and summer, while perennial plants are often used to provide focal points in autumn and winter. Some common spring-flowering plants include daffodils, tulips, polyanthus, forget-me-not, primula, ranunculus, pansy and wallflower, while geranium, salvia, begonia, nicotiana, dahlia, impatiens, lobelia, petunia and verbena are plants that flower in the summer. Chrysanthemum, penstemon, aster, Liriope and Kniphofia produce flowers in the autumn, while some of the most well-know winter-flowering plants are the hellebores (winter roses).