Four Season Gardening
I've moved out into the gardens to begin fall season cutback. It's early, but if I don't start now, with over a thousand perennials in a dozen gardens, I won't finish up by mid-October. I'll leave plants that are showing color, getting ready to show color, and the Peony foliage.
Pruning back herbaceous perennials (plants whose upper growth dies back through the winter months) now has three advantages: Spring growth will be hardier and healthier than growth that would otherwise have to force its way through dead, matted foliage or be damaged by even the gentle removing of dead foliage next spring. Removing foliage now will eliminate potential breeding havens for pests to overwinter. Aesthetically the garden is "winterized" leaving no dead remains to clutter the landscape. I've been shearing grass and spent groundcovers, including the nepeta, with my cordless shears and using the weed whacker to go through the bigger gardens. The shears are nice to use close to the base of trees, shrubs, and perennials where a weed whacker could, in a flash, harm trunks, branches, and stems. As you cut back the perennials the ground becomes exposed causing an increase in the soil drying out. Since many perennial roots are near the surface, continue watering while daytime temps are warm.
Check soaker hoses and drip systems for nicks or clogs that will reduce efficiency. Soaker hoses and drip systems deliver water directly to the roots keeping water off foliage and blooms, are self-draining, and can be kept in place for several years without replacing when maintained. After cutting back all the perennials, hopefully done by Oct 15th, I'll apply a slow-release fertilizer and topdress with amendments. I use Osmocote at the rate of 1 pound per 100 sq. ft. of garden area. Since it's temperature activated, the fertilizer will not become available to the plants untill next spring-early summer when the plants need it.
Topdress with amendments including, peatmoss, compost, manure, and finely chopped bark materials, as feeding the soil rather than feeding the plants (fertilizing). Amended soils retain water and nutrients giving both back when the plants need them. Amendments improve soil tilth and allow plants to develop a stronger root system. Overall, I have the best results from using a combination of bagged manure, peat-based product, and finely chopped bark product. I mix equal parts in my wheel barrel then toss it over the gardens. Keep crowns that overwinter with their foliage, examples; Lychnis and Poppies exposed. Mulching/Topdressing is an important chore since it will insulate roots, deter weed germination and growth, be aesthetically pleasing, and improve the overall texture of the soil. I like to mulch/topdress with a very small/fine bark in the gardens since it decomposes within one to two years.
After the trees and shrubs loose their leaves, they can be pruned.
Without their leaves it is easy to see the branching structure. Thin overgrown shrubs by pruning older branches at ground level. This will sacrifice some spring flowers but will allow more light to reach the center of the plant, strengthen new branches, and allow winter winds to pass more freely through the plant. Likewise, trees are pruned to remove unhealthy branches and add shape and structure to the plant. Most arborists agree that no more than 15% of the overall plant should be removed each year. A light, regular pruning keeps trees and shrubs shaped and vigorous.
Adjust the irrigation clock and schedule less frequent watering.
The back lawn and some developed areas are on a sprinkler system and the controller has been set to water during the early morning hours for one-30 minute cycle. It's quite likely that the lawn will be watered for the last time this season right after the last mowing for the year within the next two weeks. Most of the gardens which include trees, shrubs, and perennials are on soaker hoses. Thoroughly soak all landscape plantings before shutting systems off for the season in early November.
Schedule a lawn aeration and sprinkler system blowout.
This is a late-fall chore and follows the last lawn mowing after the leaves have been raked. The lawn should be watered, but not soaked, just before the aeration. I have learned (the hard way) to flag sprinkler heads to avoid their being damaged by the heavy aeration equipment. I like to apply an end of the season lawn fertilizer and Ironite after the aeration and just before a cold rain or wet snow is in the forecast. The fertilizer will then be available for the lawn next spring.
Keep surrounding, undeveloped areas mowed to reduce fire hazards and eliminate breeding areas for grasshoppers. The tall perennial grasses that are prevalent in this area dry quickly through the heat of summer and need to be mowed. Without irrigation/rain through summer, these grasses can easily ignite. With irrigation, they are a breeding haven for grasshoppers and draw water away from ornamentals in the landscape. We have limbed up a few of our pines so that we can mow around the base eliminating the need to hand-pull the grasses that grow up through the lower limbs. The benefits to leaving the lower limbs outweigh the ease of mowing benefit, so all but a few of our pines have been left with their natural shape.
Seasonal changes are one reason so many of us enjoy living in this area. Year-round interest in the landscape lies in planting a balanced mix of well-suited trees, shrubs, perennials, and annuals. An over reliance on any one feature can leave the gardens looking dull through much of the year. We've all seen landscapes that are primarily lawn. Usually flat/one-dimensional with little design creativity and certainly no appeal to songbirds or other beneficials. On the other hand, designs that include a diversity of plantings provide four-season interest, are much easier to maintain, and allow us to enjoy spending time outdoors.