Cultural control is the manipulation of the environment to avert serious pest damage. It depends on knowledge of both the plant's needs and its potential problems. For example, most plants have an ideal site in which they will flourish. In a poor site, they become stressed and prone to greater pest attack.

• Start Right. Select plants adapted for the site you have in mind. For example, rhododendrons need good drainage, moisture, and an acidic, organic soil. If planted in poorly drained, clay soils you will subject them to root rots. Many junipers cannot handle wet, poorly drained soil for the same reason.

  Avoid using key plants or "pest-prone plants." Other examples of key plants include skimmia (chronic spider mite problems), spruce (chronic aphid problems), and many crabapple varieties (powdery mildew and scab problems).

  Genetic expressions (leaf type, toxins in plant) make certain varieties resistant to pests whereas others of the same species are quite susceptible. For example, many rose and crabapple varieties are disease resistant, and several rhododendron species and varieties are almost immune to leaf notching by root weevils. Ask known experts about them or consult extension publications.

• Water Management. If for some reason you intend to change the moisture profile in the landscape, consider the impact it may have on plants. For example, when installing a lawn sprinkler system, consider where the sprinkler heads will be in relation to junipers, or conversely, consider where you should not plant junipers.
  
• Induced Competition. This can be accomplished by establishing dense groundcovers that can reduce weeds by outcompeting them.
  
• Remove Plants. Roguing is a perfectly viable cultural tool. If a plant consistently has pest problems, consider replacement with a more dependable species.
  
• Modify the Environment. Maximizing air circulation in tree or shrub canopies through pruning or by plant spacing can be another way to avoid serious pest buildup (e.g., proper pruning of apples can reduce scab; spacing roses to enhance air circulation can reduce powdery mildew and black spot diseases).

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