Preparing Your Garden for Winter Weather

Now in early November, the sun noticeably takes a shorter path across the sky, arching low on the southern horizon. This seasonal tilt of the earth away from our star, the sun, is expressed in the landscape by long shadows and most dramatically by shorter days and long cold nights. Plants in our garden respond on cue to this seasonal variation. The green chlorophyll on the leaves’ surface of our hardwood trees sloughs off into the atmosphere, gradually revealing the yellow, orange and red pigments hidden all summer long under the green layer of chlorophyll. Now exposed, these colorful pigments provide a brief, yet stunning show of autumn color.

With winter approaching, the cooler soils slow root growth until the entire plant falls into winter slumber. The gardener in response to diurnal variations, noted by shorter days, temperature swings and the increase in relative humidity, must adapt and focus on a new garden routine.

Here are a few helpful gardening tips to focus on while preparing your garden for winter.

1. Reprograming your Irrigation Clock – Adjust your irrigation clock by reducing the run days (frequency) from three days a week to just one. And, after the first half-inch of rain, manually shut off your irrigation clock. Then monitor plants by visually recognizing what they are telling you. Look for the angle of the leaf axil to widen, indicating early wilt. Look for leaf color change, going from dark green to faded yellowish green leaves. Look for the leaf finish to go from glossy to dull. Any of these symptoms are indicators to irrigate (soil moisture meters are free and available from the City of Beverly Hills — call Ms. Debby Figoni, water conservation administrator, at (310) 285-2492 to receive your free soil moisture meter).

When winter rains arrive in November and a rainstorm drops ½ inch of rain or more, (you need a rain gauge in the garden to accurately determine the amount of rain — your irrigation must be off) it is a good practice to manually shut off your irrigation clock for several weeks while monitoring your plants for stress as described above. In a normal rainy season, (the average rainfall in Beverly Hills is 16” per year) the irrigation can be turned off during the entirety or at least intermittently during the five-month rainy season. Regardless, you need to visit the plants in your garden in the later afternoons to determine if they are thirsty and showing signs of drought. If so, run the irrigation once and then wait for the next rain or the next time plants show wilt and then manually water them.

2. Leaves and Wood Mulch – Add a layer of organics on top of the native soil to protect it from compaction during irrigation and rains. Carefully apply the mulch around the plants, but do not allow the mulch to sit in the “crown” or growing point of herbaceous plants. This can cause crown rot and death of the plant. Also, mulching deeper than 1 inch is detrimental to water and air penetration into the soil. Fine wood mulch and recycled (small) leaves from your garden can be an attractive mulch. And, as it breaks down, it adds nutrients while helping retain soil moisture. Mulch will also deter weed seed germination. Be sure to tell your gardeners not to blow the mulch out of the planting beds. This results in blowing the finest, most fertile soil particles into the air, rendering them useless to plants because they settle on your plant leaves, sidewalks, window sills, and, most annoyingly, your cars and deep in our lungs.

3. Root Pruning and Transplanting – Roses and other deciduous plants can be transplanted in December after leaf loss. You may need to aid in the process by physically removing the leaves. In the next few weeks, use a long-nosed shovel to circle the plant by inserting it into the ground about 8 to 12 inches, making the circle about 15” from the stem. This will cut many roots and result in new root growth closer to the trunk of the plant. This decreases stress on the plant and assures survival when it is dug and transplanted in mid-January.

4. Avoid Pruning Tender Evergreen Plants – It stimulates new growth that is cold tender! Do NOT prune azaleas or camellias because they are budding; same for citrus that begin blooming in February. Do prune in January roses, deciduous fruit trees and grape vines.

5. Plant Natives – With rains due to arrive starting in November, native plants should be planted into the ground with shallow basins around them. Hand water until Mother Nature delivers our first ½ inch of rain and then monitor and hand water the plants only if needed. By summer, their roots will be established, and they will need little irrigation water. There are many wonderful native plants at VRG; especially beautiful in spring is the blue ceanothus and the yellow flannel bush, both located in the Italian Terrace Garden. The front meadow is seeded entirely with California flowering perennial plants.

6. Plant Fall Vegetables and Winter Flowering Annuals – Cool season plants need a sunny location in the garden. Now is the time to plant from color packs, broccoli, cauliflower, brussel sprouts, and many types of lettuce, spinach and kale. Plant by seed carrots, radishes, turnips, beets, and onions. Favorite flowering annuals include violas, pansies, primula, snapdragons, blue forget-me-nots with orange and yellow nasturtiums.

By following these simple tips, your garden will grow ever-greener, while providing sustenance and a sense of joy and wonder to you and yours during this winter season!

Post by Timothy L. Lindsay
Superintendent of the Virginia Robinson Gardens