A: As always, it depends, says Yvonne Carree, UI extension forestry associate. A fully mature tree that has always leaned has adapted to that position and is perfectly safe, she says. "The beauty and uniqueness of these trees should just be enjoyed as they are."

On the other hand, if a fully mature and formerly straight tree has recently begun to lean, you'd be well advised to get out of the way. A root rot is probably undermining the tree's stability. "The best thing to do in this situation is to remove the tree."

If your leaning tree is young, healthy, and under 25 feet, you can try to straighten it with pruning. Move the tree's center of gravity to a point more central over the trunk by cutting back the leader and the lateral branches on the "downwind" side to more upright branches.

Q: We moved into a new home five years ago. After several years, the lawn began to develop small, light-green to yellow patches in the spring. The patches have since expanded every spring, cleared up every summer, and returned every fall. What's the problem?

A: It sounds like necrotic ring spot, quickly becoming the most important fungal disease of Kentucky bluegrass in the Pacific Northwest. Typically, actively expanding patches have a border of reddish-brown turf, and other grasses and weeds may have recolonized the centers. Infected plants lift easily from the soil to reveal blackened roots.

According to Krishna Mohan, UI extension plant pathologist, excess thatch, overfertilization, overwatering, and inadequate soil preparation prior to lawn installation all can predispose a lawn to necrotic ring spot. This soilborne disease spreads through contaminated soil as well as lawn mowers.

FortunatelyÑwhile expensiveÑeffective fungicides are available. They should be applied in spring before the symptoms reappear. Control, however, may not be readily apparent until late summer or fallÑand seeding over the existing grass may still be necessary to recover the lawn.

To prevent recurrence, put your lawn on a proper irrigation and fertilization program. Water deeplyÑnot frequentlyÑand remove excess thatch. Ask your UI county extension educator for lawn care recommendations for your area.

Q: I repotted a large grape ivy into a plastic hanging pot with a reservoir built into the bottom of it instead of a drainage hole. Water was supposed to collect in that reservoir and prevent root rot, but it looks like my ivy is rotting anyway. Is there anything I can do to rescue it?

A: "It's been my experience that houseplants tend to be overwatered by those who love them," says JoAnn Robbins, UI extension educator. Robbins says "only three things keep them free of root rotÑand therefore alive": (1) holes in the bottoms of the pots to drain the excess water out, (2) clay pots that evaporate additional water from the sides, and (3) loving plant "parents" who occasionally forget to water.

Once the built-in reservoir at the bottom of a plastic hanging pot fills with water, it keeps the pores of the soil pretty well saturated. Because root-rot fungi thrive in saturated soil, and because the plant is already stressed by its suffocating conditions, the end result is root rot.

Robbins does not recommend fungicidal soil drenches. To try to save your plant, unpot it and knock off as much old soil as possible without destroying the root ball. Discard that old soil: it harbors root-rot fungi. Using new soil, repot the plant into a container with good drainageÑthen stop overwatering.

"Even with these efforts, the plant may continue to decline," Robbins says. "In that case, discard both the plant and the soil and buy a new plant."

Q: We're really partial to acid-loving plants such as azaleas, rhododendrons, and Japanese maple. Rather than continually battling our alkaline southern Idaho soils, can we just grow these plants indefinitely in large patio containers?

A: Azaleas, rhododendrons, and Japanese maples can perform well in containers for a long time, but they're not likely to thrive in them indefinitely, says Bob Tripepi, UI horticulturist.

Because their roots are even more susceptible to temperature extremes than their shoots, successfully nurturing these containerized plants through summer highs and winter lows can be challenging. Include their demands for critically timed irrigation and for proper fertilization, and maintaining these container plants can add up to an ambitious task.

Nevertheless, these species are so rewarding that you may well decide to persevere. If you do, choose pots that are at least 15-gallon size, or about 2 feet cubed, for species that won't grow taller or wider than 3 feet. Use 25-gallon potsÑ4 feet tall by 4 feet wide by 3 feet deepÑfor larger species.

"Young plants that grow larger each year should be repotted after several years so that the circling roots don't grow too much and strangle the plant," Tripepi says.

Use containers with holes in the bottom. To optimize drainage, also use a soil mix that is high in organic matter. A mix of 70 percent pine or fir bark, 10 percent peat moss, and up to 20 percent garden soilÑby volumeÑwill drain well, retain added fertilizer minerals, and provide enough weight to keep the plant from blowing over.