Q: We had extensive landscaping done in February 2010 and mostly we love it. But not everything is thriving. Our Rudbeckia hirta has collapsed in the middle as though something squashed it. Now another clump has the same problem. Should I divide them?
Jill McIntosh,
Coquitlam
A: Yes, your Rudbeckia should be divided. The middle is getting congested and the old roots there have become exhausted. If not divided, it will eventually cease to flower in the middle. Many of the taller, mat-forming perennials need frequent division.
You should replant the vigorous shoots on the outside and discard the less-productive centre. This can be done in fall, but spring growth makes a faster start.
Q: I have a giant philodendron plant that has outgrown its pot and even the doorway and is practically reaching my ceiling. It looks sad and needs help. Could I chop off the top and replant that?
Jean Konda-Witte,
Abbotsford
A: Philodendron vines are reputed to shoot back vigorously from hard pruning. Theyre even said to grow new plants from slices of stem. So your idea about chopping off the top and replanting it might work, though youll have to remove almost all the branches down to one or two leaves each because a plant with no roots wont be able to support a lot of green stem and leaves.
But for your large and very old plant, this would be an extremely stressful experience. Youd need to plant your philodendrons top in well-drained soil and water frequently, making sure it stays moist without sitting in water.
Since your plant is tropical and will be inside, I dont think the time of year will make a difference to pruning results. So fall or springits your choice.
An alternative plan is cutting back some of the philodendrons long branches to fit your space better but leaving some green growth. The plant should respond by putting out new growth points on the stem and lower branches or as side-shoots on the leafy stems you left.
But before you make a major cut, why not make sure a young philodendron is waiting as a backup? Just take a couple of four or five-inch pieces, remove any leaves that would be in soil, apply rooting hormone in shallow slits near the bottom end and plant in potting mix. Keep the cuttings watered. They should root quickly.
As soon as they start growing, youre in a safe position to slice off your philodendrons head and replant it. Cutting her trunk down to a foot or so might also trigger new shoots.
Anne Marrison is happy to answer garden questions. Send them to [email protected].
