By David Walther, Butte County Master Gardener, June 27, 2014
The on-going drought is leading many gardeners in our area to include drought-tolerant plants in their gardens, or even design wholly drought-tolerant landscapes. Here are some tips for selecting, planting and caring for plants that prefer dry conditions.
Most drought-tolerant and dry-loving plants do not like water on their stems or crowns. Wet conditions can trigger crown rot, so make sure you are correctly watering the plants you already have.
If you have a drip system installed, you can offset the emitters to keep the crown dry or deliver water directly to the roots of the plant by locating a piece of plastic watering pipe (any dimension you have around) from ground level to the bottom of the root ball. Slide an emitter inside that pipe, and voila! You will be safely watering your plant and avoiding crown rot. If you already have a dry garden set up with emitters, make sure those drippers are not getting the stems of your plants wet.
If you are planning to put in a dry garden, summer is not the best time to do it. The optimum time to plant a dry garden is between November, when the first rains begin to fall, and February. Planting during that period gives plants a chance to establish roots before the summer heat arrives, and before the soil begins to dry out.
You can start work on a dry garden now, though, by collecting plants from local nurseries and keeping them in a holding area in your yard until planting time. It is especially helpful to purchase plants right at the time they are at their best in terms of foliage or flowering so you know what you are getting. Meanwhile, you can prepare the site so by late fall you will be ready to put them in their new home. There is generally no need to amend garden soil with compost for drought-tolerant plants.
When putting in new plants, one method to ensure that the stem and crown remain dry is to “plant” a plastic nursery pot (like the one the plant came in) next to the plant – about ten inches away from the stem – leaving one to two inches of the pot above the soil line, so the bottom of the pot is in line with the lower part of the plant's root ball. Keep this pot empty, and when you water, water inside the pot instead of at the base of the plant. Water will seep through the holes in the pot and water the roots of the plant. After the first winter, the roots will have developed and the plant will be able to survive with less (or no) water, at which point you can pull up the pot and fill in the hole.
Once in place, water plants weekly for the first year; after that they can grow with just an occasional watering. Some will thrive with no water at all, except that which Mother Nature provides.
Consider some of the following plants for your dry garden, and keep in mind that many California native plants are drought-tolerant.
You can intermix your sun-loving dry shrubs with flowers that will grow with zero water, for example: scabiosa, calendula, nigella, California poppies, Mexican hat (Ratibida columnifera), iris and stock.
Shrubs well-suited to shady locations include daphne (Daphne odora) which resents a wet crown, and Oregon grape (Mahonia aquifolium).
Flowering plants for shade include lily of the valley; lambs' ears (Stachys byzantine); rose campion (Lychnis coronaria); native bleeding heart (Dicentra formosa); and spreading cyclamen (C. hederipholium).
For ground cover in dry shade try Epimedium spp., which has tough leaves and star-shaped flowers and will grow in shade; mayapple (Podophyllum peltatum); and lamium (L. galeobdolon).
The availability of drought-tolerant plants may vary, so check with your local favorite nursery to see what they currently have and/or plan to stock.