QUESTION: We have gotten some estimates for lawn treatment, and one of them indicates that we have the weed nimblewill and that it is uncontrollable.ANSWER: Nimblewill (Muhlenbergia schreberi) is indeed very hard to eradicate. It is a grass that spreads by stolons, intermingling with desirable lawn grasses. In winter, it dries and turns straw color; in warm weather, it is a shaggy look-alike for southern Bermuda grass.The only advice I've seen that seems to have potential is to spray the patches of it with an herbicide (such as Roundup), being sure to spray a few inches beyond the perimeter of the patch. This will kill everything, including any good grass that is mixed in. After the nimblewill dies, rake the spot aggressively and then reseed with good grass seed. This is probably best done in August, optimal time for sowing grass.

QUESTION: I would like to plant some rhododendrons against the foundation on the east side of my house. It gets morning sun, but afternoon shade. Somebody told me they would not do well there - is this true?ANSWER: It can certainly be done. Morning sun and afternoon shade are usually a good setup for rhododendrons, but your situation requires precautions.First, check out the soil. The danger near a foundation is that crummy soil was backfilled at construction, with the added concern of concrete debris, which can make the soil too basic (i.e., not acidic). Replace or amend the soil as necessary. Rhododendrons need porous, well-draining soil high in organic matter. Then, don't plant too close to the house. Rhododendrons will eventually be crowded against the wall if not placed 3 to 4 feet away.The other concern has to do with sudden rising temperatures when the sun hits the spot in the morning. Young plants are vulnerable in the winter. After a night of deep cold, a blast of sun (especially if the wall is a light color) can swell the tissues in the stems and result in bark split, which can kill the stem from that point up. Older plants are less susceptible.Don't choose early-blooming varieties; the unnatural warmth of the site will cause the buds to expand too soon, and they're likely to be zapped by hard freezes. Most "classic" big-leaf rhododendrons aren't early bloomers, so it won't be hard to find an appropriate variety.Send your gardening questions to Michael Martin Mills, The Philadelphia Inquirer, Box 8263, Philadelphia, PA 19101, or send e-mail to: Millsmphillynews.com