If I had to do just one thing that would improve any garden, I'd add mulch.
Basically, mulch protects the soil and fosters a larger and more diverse population of underground life. The worms, bacteria, and fungi that do all the work underground need water, nutrients, air, and moderate temperatures. Mulch provides all of these: it holds in moisture, which also keeps your water bills lower; it leaches nutrients as water trickles down through it; it slowly adds organic matter and helps loosen compacted clay soils, adding air spaces; and it keeps the soil warmer in winter and cooler in summer.
For native plants, mulch also helps feed the mycorrhizal fungi that connect the plants' roots to each other. Overwatering is especially deleterious to natives because it destroys this fungal net. Excess water fills the air spaces in soil and favors the growth of anaerobic bacteria, which not only consume the beneficial fungi, but also deprive plant roots of air and cause disease.
Finally, if your garden is newly planted, mulch gives the landscape a neat, finished look until the plants fill in.
Four to two inches of mulch is the recommended amount – that's about a cubic yard for every 80 to 160 square feet – but I've seen as little as an inch of mulch make a difference, and I've used 6-8 inches of mulch (with cardboard underneath) to suppress noxious weeds.
Use a mulch that stays loose and lets water flow through, not a fine-grained type that packs together and keeps water out. Keep the mulch pulled away from stems and trunks, so that moisture will not collect there.
Mulch is most economical by the truckload. You can buy mulch at a garden supply yard, or – if you are less picky about the uniformity of the mulch – you can get it delivered free from tree trimmers.
After mulch, the second best thing for a garden is an attentive gardener. Spend time in your garden every day. The better you know your garden, the easier it is to notice little things and to correct problems while they are still minor.
Frank Niccoli of The Village Gardener, at a recent panel discussion on watering native plants, stressed the importance of knowing the personality of your garden. He talked about getting to know your “indicator plants” – the ones that wilt first.
Gardens that use spray or drip systems are usually overwatered, Niccoli said, and hand-watering is the most efficient system for a typical suburban garden. Natives are not amenable to watering schedules, he said. Stick a finger in the soil to see if the soil is moist or dry, and add water only if the soil is dry, Niccoli advised.
A few natives, such as fremontia and woolly blue curls, need water only when they are planted; most need water for the first two to three years, until they have established root systems sufficient to withstand drought. Watering by hand is an especially good way to focus on a new garden, as you watch your young plants grow and flourish.
© 2006 Tanya Kucak