Rescuing houseplants, pruning butterfly bush

Maybe you can help me with my Spath, which keeps getting black borders on its leaves and eventually dies. I have cut these borders off; the plant is in front of a window (not sunny), and I water when it's dry. I do fertilize about once every other month. Can you help me save my plant?-- Eve Rosen, Port Washington

Spathiphyllums, or peace lilies, are houseplants that require low-to-medium light levels and above-average watering. It's possible to go overboard with the water, which can result in Pytophthora, or root rot, which will wilt, blacken and eventually kill the plant. Poor drainage and over-fertilization also can contribute to the disease. Spaths should be fertilized only during the growing season -- spring through late summer -- and kept away from cold drafts and strong sunlight.

Gently lift the plant out of the pot and check the roots. If they're completely yellow, brown, red or otherwise discolored or mushy, then you can kiss it goodbye. If they're not, try trimming away any blackened foliage and discolored roots and repotting the plant in a sterile, soilless potting mix. If your plant continues to decline -- and only then -- try giving it a dose of a systemic fungicide like fosetyl aluminum (AlietteR) or metalaxyl (SubdueR).

Clip 'wings' of butterfly bush now

Thank you so much for your monthly calendar. It helps so much! I see this month that you say a butterfly bush can be pruned. Can it be transplanted at this time also?-- Peter DiFiore, Medford

Yes. The best time to transplant a butterfly bush is while it's still dormant. March is the perfect time because the ground begins to soften, making the task easier, and the plants haven't yet begun to leaf out. First, dig the new hole, then carefully dig up as much of the root system as possible. Replant immediately so the roots don't dry out, and mix a generous helping of compost into the backfill. Be sure to water the plant regularly throughout the first growing season until it becomes established in its new home.

Key to avocado is humidity

My son is trying to grow an avocado tree indoors. It is about 3 feet tall, and the leaves are beginning to turn brown and fall off. I have it near a window that faces morning sun. What can we do to make sure it doesn't die? Does it need a big pot, drainage, less sun or water? Please help. -- Rose Trestka, Coram

Avocado leaves can turn brown for several reasons: low humidity, common indoors during winter, could be to blame, as can insects, too much fertilizer or insufficient watering. To increase humidity place the pot in a tray or large baking pan filled with pebbles and an inch or two of water (not so much that the pebbles float).

Avocados require well-draining soil and deep, infrequent watering. Put the tree in the sink (or bathtub, if it's very large) and water thoroughly until water drains from the holes in the bottom of the pot. Then don't water again until the soil dries out. Fertilize with ordinary houseplant fertilizer diluted to half-strength from now until fall. And if you want to put it outdoors for the summer, place it in the shade.

Bay laurel likes sun, moisture

I have been trying for about 4 years to grow bay leaf. Each spring I purchase a plant and it grows well outside. When the temps get too cold, I bring it into the house. It stays in the same pot. Every year the same thing happens: After a month or so it dries up. Any ideas would be so appreciated.-- Terry Guido, Williston Park

Bay laurel is a tender perennial that won't survive our winters outdoors. Though it can be brought indoors in autumn and grown as a houseplant until spring, it requires full sun and moist, but not soggy, soil to thrive. Keep it away from radiators and heat vents. I suspect your plants are too close to heat sources or aren't getting enough water. Once they begin to dry up, there's no bringing them back.

For windmill palm: Think cool

I bought a windmill palm tree last spring, and it was doing fine all summer. When the weather started to get into the 30s, I brought it into the house and watered it once a week. Gradually, the leaves started turning brown/black, but they haven't fallen off. It has developed new leaves over the winter, and a few of them have also turned. I think it is in a big enough pot for the size. I haven't given it any fertilizer, just water. Do you know of anything I should be doing for it? -- Bob Peters, Bayport

Windmill palms are appreciated for their cold hardiness. They're suited for areas that get as cold as 5 degrees, just outside our reach, so they do need to be brought indoors over the winter, as you've done. Once inside, they prefer to remain on the cooler end of the room-temperature range, so perhaps the heat in your home is stressing them. Browning leaves also can be the result of a fungal disease, iron or magnesium deficiency or underwatering. Palms require relatively moist soil that drains well. Push your finger into the soil and water whenever it begins to feel dry just below the surface. Be sure there are drainage holes in the pot, and don't allow water to sit in the saucer. For now, trim away the discolored portion of leaves, and apply a fertilizer indicated for palms that contains minerals from now through autumn, following package directions. Also, keep the leaves free from dust. Good luck!