Watch your walkway with this vigorous grower

Q: I am considering Lotus corniculatus 'Pleniflorus' for a walkway. The plant's label indicates that the growth rate is fast, but is it invasive? Will I be trying to prevent it from spreading into nearby beds?

A: While this double-flowering form of bird's-foot trefoil grows to form a thick mat dotted with pretty yellow flowers, you're wise to be concerned about its fast growth. In some areas of the Northwest, this hardy ground cover has proved to be invasive. To avoid potential problems, you might want to choose a less-vigorous ground cover.

Q: I would like to know the scientific name for the prostrate coast redwood. I tried a search on "Sequoia sempervirens prostratus" but did not come up with anything.

A: If you love the soft, feathery foliage of redwoods but don't have space in your garden for such giant trees, go for the dwarf version. Sequoia sempervirens 'Nana Pendula' or S. sempervirens 'Prostrata' grows into wide, needled mounds that are more ground cover than trees, yet with the same appealing foliage as the world's largest trees.

Q: I wonder if you could give me some suggestions for climbing, rambling roses to cover a trellis over our back door. The area is approximately 10 feet by 10 feet, in full sun and next to flower beds.

I would ideally like a very fragrant, continuous-blooming, disease-resistant rose that is suited to the Northwest climate and not too particular about heavy watering, feeding or fancy pruning. And definitely no spraying.

I have found it extraordinarily difficult to find any books offering the sort of advice I want — e.g., staggering the bloom times of once-flowering old roses, fragrance ratings, etc. Thank you for any help you can give me.

A: For a comprehensive look at climbers and ramblers, take a look at "Climbing Roses of the World," by Charles Quest-Ritson. For growing roses in our corner of the country, check out "Roses for the Pacific Northwest," by British Columbian rosarian Christine Allen. You'll find here all the details you'll need on scent, size, health and bloom time, tailored to our uniquely challenging rose-growing climate.

Allen recommends Rosa mulliganii, which has fragrant, golden single flowers and thrives on neglect. I've had good luck with the climbing 'Iceberg' and 'Sally Holmes,' both of which are pale, fragrant and long-blooming.

Rosa 'La Bonne Maison' is a modern climbing rose bred in France, with flowers that repeat bloom from early summer until first frost. It has single white flowers with a pink reverse, a strong, sweet scent of cloves and showy red hips in autumn.

One of my favorite roses is the multiflora rambler Rosa 'Ghislaine de Féligonde,' a trouble-free, delicate rose with double apricot flowers that bloom off and on all summer.

Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Write to her at P.O. Box 70, Seattle, WA 98111 or e-mail planttalk@seattletimes.com with your questions. Sorry, no personal replies.