Drought Tolerant Plants for New Hampshire Landscapes [fact sheet]

Rainfall patterns are can be highly variable in New England. Periods of above-normal precipitation may be followed by weeks with little or none. While many established trees and shrubs can tolerate two weeks or even longer without water, they may show signs of reduced growth, nutrient deficiencies, and/or increased susceptibility to certain pests and diseases during a prolonged drought. New plants need frequent watering for several weeks or even months (for large shrubs/trees) to establish their roots in the surrounding soil. Even short periods of hot, dry weather can threaten the health and survival of newly planted trees and shrubs, vines and perennials. Annual flowers (bedding plants) generally suffer first from drought because of their limited root systems.  

Homeowners and landscapers who want to minimize irrigation needs or who live in areas with potential water restrictions should select plants which can tolerate drought. This does not mean xeriscaping, which is more appropriate for arid environments such as the Southwest. Many xeric plants cannot stand the wet conditions that are likely to occur during part of our growing season. Instead, choose plants that can withstand New Hampshire’s variable climatic conditions, not just occasional drought.

To get the right plant for your site, consider other characteristics in addition to drought-tolerance. Good soil drainage is especially important for many drought-tolerant species to thrive. Sun and shade patterns, soil characteristics, and wind exposure, as well as mature size and shape, insect or disease susceptibility, and aesthetics are all important factors in selecting appropriate plant material. Evergreen plants generally need less water than deciduous trees and shrubs during the growing season, but more during the off-season. Broad-leaved evergreens such as rhododendrons and mountain laurel, although not considered drought-tolerant, grow best in partial shade which offers some protection from dehydration. Needled evergreens (conifers) as a group have the lowest water requirements.

Keep in mind that even drought-tolerant plants need ample water initially to encourage root establishment. Once established, in most years they require little or no water other than natural rainfall. When no rain occurs for a period of two weeks or more during the growing season, check on shrubs, trees and perennials and water the root zone thoroughly if they are showing signs of wilting or stress. Check annual flowers daily.

This list of drought-tolerant plants was compiled using several references, along with our own experiences where possible. The plants included here are cold hardy to zone 3 or 4 and are generally considered to be desirable landscape plants (not weedy, invasive, brittle, or especially pest-prone), but these criteria are always changing. Consult the references for the most current common and scientific names and any concerns about potential invasiveness.  Most of the listed plants should be available at local garden centers and nurseries.

Deciduous Trees

Deciduous Shrubs

Evergreen Trees and Shrubs

Ground Covers and Vines

Perennials

Annuals

Ornamental Grasses, Ferns and Sedges

References

1. Missouri Botanical Garden. 2018. Plant Finder. St. Louis, MO 63110. www.missouribotanicalgarden.org/plantfinder/plantfindersearch.aspx  

2. New England Wild Flower Society. 2018. Go Botany! https://gobotany.newenglandwild.org  Framingham, MA 01701.

3. Swearingen, J., C. Bargeron. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health. http://www.invasiveplantatlas.org/

4. USDA, NRCS. 2018. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901. http://plants.usda.gov