What are Perennial Plants?
Perennial plants are plants that live for two or more years. Perennial plants grow for several years and go through repeated flowering and seed producing cycles before they die or put out one seed production cycle, and then die. Perennial plantings serve as a foundation for your garden and can serve various purposes such as:
• attracting wildlife and providing habitat for beneficial insects such as pollinators and predators
• food production (such as fruit trees and vines)
• medicinal uses
• ornamental uses
Perennial plants are usually easier to maintain than annual vegetable crops and once planted perennials provide a place of beauty and interest for years to come.
There are many considerations to take into account when selecting perennials:
• evergreen vs. deciduous (green year-round or lose their leaves)
• flowering, fruiting months and colors – it makes most sense choose plants that will fruit or flower when school is in session.
• size and structure – will the mature size of the plant your are planting fit properly in the space you are planting it?
• uses of plant (culinary herbs, ornamental uses, medicinal uses, habitat, food production, ect)
• light requirements – will the plant you are planting receive the appropriate amount of light throughout the year
• appropriate climatic zones
Climate Zones for Perennial Plants
To determine which plants are suitable for a climate zone gardeners refer to hardiness charts or “climate zones”.
There are two zone charts that are commonly used in the western region: the USDA Zone and the Sunset Western Garden Zones.
The USDA Zones range from 1-11, with one being a colder zone with annual average minimum temperature of –50F or below and 11 being a warmer zone annual average minimum temperature of 40F or above. In California most locations fall between zone 7-10.
View the USDA Zone map.
The Sunset Garden Zones are similar to the USDA Zones but are more detailed allowing for a more specific match of a plant's ideal environmental preferences and a location's climate. There are 24 Sunset zones and the Sunset Western Garden Book is an indispensable resource that lists thousands of plants, their zones and growing information for the Western US.
Learn more about Sunset's climate zones.
To find out your specific zone ask your nursery professional, contact your County's Master Gardener www.mastergardeners.org , or view the zone maps listed above or download this map of Sunset and USDA California Climate Zones.
To find out what zone a particular plant will thrive in refer to the plant label or a resource such as the Western Garden Book.
Here are a few more points to consider when planting perennials:
- “Herbaceous” perennial plants die back to the ground in the winter and regrow in the spring, “Woody or Deciduous” perennials lose their leaves but not their structure, and “Evergreen” perennials keep their leaves during the winter. Keep these characteristics in mind when planning your garden's design.
- Evergreen perennials can be planted any time of the year, but for most of California the best time of year is in the fall. This allows plants root systems to get established before their growing season and to take advantage of winter rains.
- Bare root perennials such as fruit trees and vines should be planted in the dormant season (winter months or late winter months if your ground is frozen).
- Most bulbs are planted in the fall for spring blooming dates.