Mt. Cuba Center is located near Wilmington, DE, (USDA Hardiness Zone7A/6B). Multiple plants of each taxa are grown in a 15,000 sq. ft. trial garden that includes areas for growing both sun-loving and shade-loving plants. The clay-loam soil in the trial garden has an average pH of 6.5.

The Trial Garden is maintained with the home gardener in mind. Plants are watered as needed during the first year in order to get them established, but afterwards they are left on their own. Pesticides are not used unless there is a serious threat to the entire trial’s survivability.

Perennial plant trials usually run for a period of three years to ensure the plants experience a variety of weather conditions. It is our policy to replace dead plants after the first winter in order to compensate for poor establishment or initial plant quality. However, no replacements are made during subsequent years. Each taxa is evaluated weekly and assigned a rating based on a scale of 1-5 (see below). This rating takes into account many factors including habit, floral display, disease resistance, hardiness, and foliage quality. The average of these weekly ratings is then used to calculate the final score displayed on this website.

Our numerical rating system ranges from one to five and can be interpreted as follows:

  1. Poor
  2. Below Average
  3. Average
  4. Good
  5. Excellent