The mild winters of Zone 4 do not meet the cold requirement of many deciduous fruits, flowering trees and shrubs that grow in Zone 3.

On the other hand, the sub-tropicals and tender plants of Zone 5 must be protected from the hard frosts that occur here. September, October and November are ideal months for planting cool-season annuals, perennials and the basic landscape plants. This allows time for the plants to become well-established in the new location before the onset of summer heat.

Fall planting is not recommended for tender plants such as Hibiscus (Hibiscus Rosa-sinensis), Bougainvillea (Bougainvillea sp.) and Lantana (Lantana sp.), which might be injured by winter frosts.

South American hybrid mesquite (Prosopis hybrid), Xylosma (Xylosma congestum), Pineapple guava (Feijoa sellowiana), Texas ranger (Leucophyllum frutescens), Blue palo verde (Cercidium floridum) and Star jasmine (Trachelospermum jasminoides) are representative Zone 4 plants.

USDA Plant Hardiness Zone System: roughly equivilent to USDA Zone 8 (Average Annual Minimum Temperature = 10 to 20 degrees F).

Sunset Western Climate Zone System: equivilent to Sunset Zone 12 described in Sunset Western Garden Book.