Choose roses based on the 24-zone climate system established by "Sunset Magazine." The University of California Cooperative Extension encourages the use of this system because, unlike the USDA zone system, it also factors in summer high temperatures.
Adjust according to your climate. Southern California has many microclimates, ranging from moderate and moist to severely dry and hot. Roses in hotter, drier areas need more care and attention.
Plant new roses in January. Prune established roses to half their height. Thin out roses and remove excess foliage. Complete all pruning by the end of January.
Remedy problems as soon as they start. Gardeners in Southern California begin to see aphids and mildew in mid-to-late February. Apply insect control and fungicides as needed.
Feed your roses in March as they begin to develop new foliage. Supply a dose of 20-20-20 fertilizer for optimal results.
Spray for spider mites in April. These bugs harm roses. Use a miticide or wash roses by hand.
Apply a weekly fertilizer during peak growing season, typically from April to mid July.
Deadhead blooms in May. Southern California roses have two blooming cycles. Mid-May marks the end of the first. Encourage new blooms by removing spent ones.
Keep your roses watered. This is of particular import during peak blooming season, which also coincides with the hottest months of the year. Water daily through the end of October. Remember to water frequently well into fall to account for the dryness caused by the Santa Ana winds.
Complete a round of light pruning in October. Re-apply mildew and pest treatments as needed. Cooler weather allows bugs and fungi to reappear with ease.
Begin planning for your new roses in November and December.