While all of the plants in NABA's Butterfly Garden Guide are useful for butterfly gardens, NABA members have been asked to rate plants with which they are familiar. The charts that accompany each plant are an average of the ratings received to date.

Ratings reflect the following considerations:

Caterpillar food source rating: If you plant this in your garden, how likely is it that at least one species of butterfly will use it as a caterpillar food source?

• 0 - Is not known as a caterpillar food plant
• 1 - Very unlikely. Possible reasons would be that it is not the preferred food plant or because, as in the case of Round-leaved Ragwort, the butterfly species that prefers the plant as a food source (in this case, Northern Metalmark) is rare and very localized and it is unlikely that there is a population near your garden.
• 2 - Reasonable chance of use by caterpillars.
• 3 - Very likely to attract caterpillars.

Butterfly nectar value: Please consider the overall number of butterflies attracted to the plant in question, in addition to the number of butterfly species that nectar at the plant.

• 0 - Is not known as a butterfly nectar plant.
• 1 - Only weakly attractive to butterflies or only attractive for a very short time.
• 2 - Moderately attractive to many butterflies or very attractive to a few species.
• 3 - Very attractive to many butterflies.

Garden/Ornamental value: Evaluates the worth of a plant even if you are not considering butterflies. Garden value considers length of bloom period, adaptability to a wide range of settings, ease of growing and maintaining.

• 0 - A rating of '0' is not an option in this category.
• 1 - Little value as a garden plant.
• 2 - moderate value as a garden plant.
• 3 - great value as a garden plant.