I have an herb garden that stays quite dry. Although this garden is in the notoriously wet Pacific Northwest (USDA zone 8a), it is against a two story south-facing brick wall, under a large overhang, and in a sandy soil. Combining that with our rainless summers and a hard-nosed gardener who refuses to provide supplemental water after a plant's second year, it is surprising anything survives. And yet, all the standard dry soil herbs, thyme, chives, fennel, tarragon, sage, and rosemary, are all doing well in this little piece of Provence in Washington State.
I am looking for a plant (perennial) for a spot behind a rugosa rose against the wall. It must be narrow so it does not crowd the rose, but tall, 4 to 6 feet, so it stands up above the rose.
Here is the trouble: the typical tall, narrow dry-soil perennials — mulleins (Verbascum), yucca, or fox-tail lilies (Eremurus) — may have flowers that will go up above the rose, but that important part of the plant, the foliage, will be shaded by the rose. As the rose gets bigger, the problem will get worse.
A lily might be a acceptable plant choice, but lilies and dry soils do not get along well. My research tells me the madonna lily (Lilium candidum) is from the dry eastern Mediterranean, but I am skeptical.
- Have you grown madonna lilies (or other lilies) on a dry soil and succeeded?
- Can you think you any better choices?