Knowing what family a plant belongs to can be useful in making decisions about rotating plants for managing pests and soil fertility in the garden. Plants in a family are genetically related, so they have similar characteristics. As an example, members of the Cucurbitaceae, among other shared characteristics, have deeply lobed or divided leaves, separate male and female flowers on each plant (termed "monoecious" plants) with five fused petals, similar fruit types and tendrils for climbing. Besides having similarities in appearance, plants in the same family often have similar susceptibilities to various garden pests such as diseases, insects and/or nematodes.

In general, it is not recommended that an area be planted with plants of the same family in succession to avoid the buildup of shared pests. Some plants should not follow members of other families either because of susceptibility to common pests. For example, strawberries (and other members of the Rosaceae) should not be planted after members of the Solanaceae (and vice versa) because they are all susceptible to the disease verticillium wilt. Keep in mind that various weeds also belong to these same families and can also host the same pests. Knowing plant families can also be useful in determining appropriate pesticides to use, when warranted. This can apply to both targeted effects and non-targeted effects such as being toxic to desirable garden plants.

Plants can be rotated to manage soil fertility. This is done by including plants in the rotation to improve the fertility status of the garden soil and rotating among plants that are heavy users of certain nutrients. For example, members of the Fabaceae (legume family) can be grown to add nitrogen to the soil and many members of the Liliaceae are heavy users of potassium.

The table on the following pages lists several vegetables, herbs, fruit, cut flowers, bedding plants, cover crops and weeds by plant family. Plant family names can be easily identified because they end in "-aceae"; however, some families also have "old" or traditional names that end in "-ae." Traditional names as well as common names are included in the table. Note that some plants are listed in more than one grouping.

Prepared by Elsa Sánchez, assistant professor of horticultural systems management, and Kathleen Demchak, senior extension associate, Department of Horticulture, Penn State College of Agricultural Sciences.