This calendar is for the Valley. Higher towns like Sedona, Prescott, Payson and Flagstaff plant on a different schedule, and each monthly planting page has a short section for them.
The short version
October is the best month to plant almost anything in the low desert. June is the worst. Fall planting gives roots a full cool season to grow before the first summer.
Month by month
October and November
The best window of the year. Soil is still warm enough for roots to grow, air is cool enough that nothing is stressed. Plant trees, shrubs, hedges, groundcover, natives, anything.
December through February
Still good for most things. Avoid planting frost tender plants like bougainvillea, hibiscus, and tropicals until the freeze risk passes. Prune frost damage only after new growth appears, not before.
March and April
Second best window. Good for almost everything including the frost tender plants that had to wait. Get it in early enough that roots establish before June.
May
Summer starts this month. Cactus, agave and palms plant well now. Anything else planted now needs extra water and shade through the summer.
June through August
The hardest time for new trees and shrubs. Palms are the exception and root best in warm soil, and yuccas and other tough desert plants take a summer planting too. Anything else planted now needs shade cloth and water every day or two at first.
September
Fall planting starts in the second half of the month, once nights cool. Cactus, agave and palms can go in now. Trees do better if you wait for October.
Why fall beats spring
A plant set out in October gets six months or more of root growth before the first 100 degree day. A tree planted late in April gets only weeks before summer. That is why fall is the best time to plant trees and shrubs here.
What to plant this month
See the best trees, shrubs and cactus for each month: what to plant in Phoenix, month by month.
Watering new plants
Once it is in the ground, see how to water new plants in Phoenix, by season and plant type.
Cold nights
From December through February, see frost protection for Valley yards before the first freeze.