Lithodora spreads rich blanket of blue

Q: I recently returned from Seattle and while I was there I noticed many of the yards had compact amazingly dark, small blue flowers as a ground covering. I was wondering what particular plant this was. I have never seen anything like it where I live in Alexandria, Va.

A: You must be admiring the gentian blue groundcover Lithodora diffusa that is in full bloom in May (it used to be called Lithospermum diffusum).

It grows in a mounded mass 6-12 inches high, has dark, hairy leaves and is covered with intensely blue flowers that appear in a big flush in May, and then bloom sporadically through the summer.

This plant is in the borage family — hence those brilliant blue flowers that are such a fine contrast to springtime pastels.

It needs well-drained soil and does best in climates with mild summers. I'm sorry to say it probably wouldn't thrive in Virginia.

Q: I'm not the gardening type but I love flowers. My neighbor is quite a gardener and her landscaping is lovely. We have a round berm in the middle of our two adjoining properties. Would Carpenteria californica be a good stand-alone shrub? The berm is located in a sunny spot, and I'm wondering if that shrub would be a good choice for this area. Also, we have an area all around our deck (sunny) that needs colorful year-round plants that won't get too tall. Do you have any suggestions?

A: Carpenteria californica is a somewhat tender plant from California, as you can probably guess from its name. It would grow well on a sunny berm if not in a frost pocket or a chilly, windy spot. In a warm, somewhat protected environment it is one of the finest plants we can grow, because it is an evergreen shrub that grows slowly to 4-6 feet, and has large, fragrant anemonelike white flowers in June.

If you need a hardier plant for this location, take a look at rugosa roses, which are tough plants with attractive foliage and fragrant, crinkled flowers in summer.

Around your deck, a mass planting of small shrubs with especially attractive foliage would work well and not require much maintenance once they've become established. Hebe 'Amy' has glossy, plum-colored leaves and looks good in a mixed planting with colorful spireas like 'Magic Carpet' or 'Mellow Yellow.' For a more formal look, you could try clipped boxwood.

If flowers and scented foliage are desired, lavender and rosemary are both sturdy and sun-loving. With rosemary, you could lean over the side of the deck and clip a handful to toss on whatever you're grilling.

Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Call 206-464-8470 or e-mail planttalk@seattletimes.com with your questions. Sorry, no personal replies.