Northern California Coastal & Inland Valleys
I can't stress enough how important it is to frequently check your irrigation system. Water pressure will cause nozzles to shift position, debris in the lines will plug heads and leaks result in dropped pressure and wasted water. Check your irrigation at least bimonthly.
Clean is Healthy
Rake and clean garden beds to remove fallen foliage and debris. Slugs, insects and fungus spores prefer trashy gardens to clean ones. By removing their favored hiding places, you reduce future insect damage and disease in your garden.
Rhododendron Tune Up
This is your last chance to prune and shape rhododendrons and azaleas before they begin to set their buds for next spring. Fertilize the plants with a high acid fertilizer after pruning to encourage maximum bloom.
Mulch around the base of ornamental maple trees. Acer japonica varieties, such as 'Burgundy Lace', will lose foliage color if reflected heat from nearby driveways and sidewalks is too hot. Mulching the surface of the soil under the plants keeps the ground cool and prevents colors from fading. Keep the layer of mulch a few inches from the base of the trunk to avoid fungus problems.
Plan Winter Gardens
Just when you thought you were done for the year, it's time to select and start seeds now for your winter annual garden. Pansies, calendula, ornamental kale, and stock can be started from seed now for planting out while the soil is still warm to the touch in October and early November. By planting from seed, you have a much larger selection of variety available, plus it's much less expensive than planting from nursery stock.