Bonus web-only content: June seemed to go on for six weeks. July was two weeks. August is lining up nicely with the Julian calendar (so far). Expect another heat wave or two. Watch night time temperatures more than daytime. If temps are in 60’s, the plants can cool off. If nighttime temps are in the 70’s, that’s a heatwave in plantspeak and requires: no pruning, pre-irrigation and expectation of some appearance of suffering or at least “non production.” Try to go with the flow of nature, including the weather. It really does make you happier. A heatwave by definition will be of relative short duration.
August can be a light work month in the garden. Continue to repair water leaks and keep up with warm season weeds. August is also perfect for the following tasks:
PLANTING: This is the big month to plant seeds for cool season vegetables such as Asian greens, broccoli, cabbage, cauliflower, leek, lettuce, pea, spinach, and Swiss chard. You can also direct-seed another crop of beans. You can plant some ornamentals, but it will be a lot easier on you and them if you wait until fall.
MAINTAINING: Citrus requires even steady moisture during these hot months and must be watered regularly. Other plants, like many California native, Mediterranean, and desert-origin species can manage on less water. Let your low-water-use plants, many of which are our spring-blooming sage, ceanothus, manzanita, and lupine, rest during the summer. However, if you wisely added narrow-leaf milkweed (Asclepias fascicularis) to your garden, you may be noticing it in full bloom or producing seeds vigorously. Many milkweed species love summer weather. If you didn’t see monarch caterpillars on your milkweed, don’t be discouraged. I’ve seen them as late as September. Don’t worry about aphids, red milkweed bug or other insects on your milkweed; it can handle it. And you don’t want to destroy monarch eggs while going after pest insects.
If your garden is less than three years old, don’t expect the new plants to be tolerant of drought. They will continue to need extra TLC until their roots are established. Deep soaking and occasional extra overhead sprinkles for a few plants is the best practice. If you live in a fire prone area, keep your plants watered so they will help slow down wildfires and reduce flying embers.
Spider mites love dusty plants. If you see cobwebs but no spiders, it’s time to hose off the plants. In gardens with drip irrigation, this is a big problem, because overhead sprinklers aren’t washing plants off. Follow your water district’s guidelines but go ahead and wash your plants off in the cool morning or after the sun has set. Avoid overhead water if it’s windy.
Cut back and divide your iris if you haven’t already done so. Prune apricot, olive, and oleanders, but avoid pruning so much you get sunburn on newer branches. Continue to deadhead roses and remove suckers and unwanted branches. Open rose bushes up to increase air circulation through the shrub. Continue to prune hedges. Keep your pruning tools clean and sanitized. Clean up fallen fruit. Support heavy, fruit-leaden tree branches. Remember to use BT anywhere there will be standing water, even in plant trays, to avoid mosquito breeding.
Skip the fertilizer during the hottest part of summer, especially high-nitrogen products. Let everything rest a little, including yourself.
If you spray with post-emergent broad-spectrum herbicides, apply it when the temperature is 85 degrees Fahrenheit or less, and when there is no breeze, to avoid phytotoxicity and vapor drift. Using a product with surfactant is important to improve penetration on toughened summer weeds. Towards the end of the month, you can start using a pre-emergent to impede germination of cool season weeds. If you have only a few weeds, hoe or dig them out instead of spraying, or investigate where the water supporting the weeds is coming from and make a change in your irrigation practices if you can.
CONSERVING: Even in years with adequate precipitation, we can still consider removing or reducing lawn. Beyond the water saving, we can support a wider range of native and beneficial wildlife including pollinators if we include more variety of shrubs and perennials, especially native, in our yards. If you need to green patch in summer, consider using a ground cover like Lippia nodiflora.
The first step in managing diseases and pest insects is identification. That’s so you don’t accidentally do more harm than good. A good website to consult is this one from UC ANR. Ornamental plants can tolerate some insect damage and those insects can be bird attractants (food). The exception is Argentine and other non-native ants; control those throughout the garden with ant bait products, switching the active ingredient every few months.
Planning any upgrades or changes to your garden for fall? Consider creating a rain garden, seasonal creek, or swale to capture and hold onsite storm water. Gardens with a big picture approach to both drought and flooding –in other words, California’s usual weather swings, are resilient and provide value to humans and wildlife every year no matter what the weather. Consider making your garden, even in the city, a connection for migrating beneficial wildlife. Can you map out a path migrating Monarchs might be able to take through your neighborhood? Is there a neighbor you can give a native milkweed to?
It’s okay to leave dried flowers on native plants. Finches and other birds will thank you for the seed they can eat. If you want to attract more birds and pollinators, it’s fine to be less fussy about trimming every plant and removing every brown stem. I invite you to push your own boundaries, to improve the efficiency and usefulness of the garden, and to share it a little more. It’s less work too.