resources : Gardening Information : Summer

More Flagstaff Gardening Info: Spring | Summer | Winter

Early Summer  

Planting. By now, cold-weather crops are planted. If some were lost to frost, try again with plants that won’t bolt (accelerated flower and seed production) in the mid-summer heat, such as lettuce, spinach, and parsley. When evening temperatures begin to stay above freezing, it’s time to plant warm-weather crops, such as tomatoes and peppers. Blankets and row covers can provide protection for tender plants on cold nights to prevent sluggish growth. Start planting summer blooming annuals and perennials. Remember to amend soil with organic materials before planting. As bulb leaves die back, remove spent foliage.

Fertilizing. Fertilize lawns, flowerbeds, and vegetables after thinning to give them a good start for the growing season. Organic fertilizers are available.

Watering. For good growth and flowering during the dry part of the summer before monsoons, water deeply, once each week under normal conditions, but more frequently when it is over 90 degrees. Many established native plants will get by with less frequent watering until the monsoons, when they will put on their show. Check irrigation periodically.

Mulch. If all mulch was removed to warm the soil, redress the soil around your plants with a thin layer to reduce water evaporation and to control weeds.

Pruning. Once early blooming shrubs have completed their flowering, it’s time for pruning. Spent spring flowers should be removed at this time so the plant will focus energy on this year’s growth. If fruit trees have produced an overabundance of fruit, begin thinning fruits to several per branch to get larger fruit.


Planting. If you are a risk-taker, calculate backwards from the expected date of the first hard frost for your location to determine when to plant a second round of quick-growing vegetables that can take the cool early fall nights (kale, spinach, onions, radishes, etc.).

Fertilizing. Feed annuals, potted plants, and vegetables monthly through the growing season.

Watering. Continue to deep-water lawns, perennials, shrubs, and trees until the monsoons arrive. Keeping lawns 2 to 3 inches in height will help protect against drying out by shading the ground and keeping it cooler. Additionally, planting lawns using native grasses such as buffalograss (bouteloua dactyloides) and blue grama grass (bouteloua gracilis), instead of traditional grass species like Kentucky bluegrass (Poa pratensis), can help curb watering needs.

Maintenance. Keep up with the weeds before they go to seed to minimize future weeding efforts. For those weeds with stout roots that are difficult to pull out completely, keep removing top growth every two weeks to drain energy out of roots.

Late Summer

Planting. Monsoon season is a great time to plant perennials, shrubs, and trees for next year. The higher humidity and frequent precipitation greatly reduces stress on new plants and gives them time to establish roots in the soil before the onset of winter.

Watering. When monsoons arrive, cut back or eliminate regular watering. Check irrigation timer clocks to be sure lightning storms haven’t disrupted any programming. Now is a good time to replace batteries since fresh batteries will be more likely to maintain your programming even with a few electrical disruptions.

Harvest Time. If cold nights are predicted, cover warm-weather crops at night. Pick crops in early stages for the best flavors and textures and to keep the plants producing.

Planning Ahead. Order bulbs for fall planting. At this elevation, spring may be a better time to plant bulbs so that they are not battling the intense cold of winter before becoming established.