Dear Helen: Can you clarify for me the planting times, growth pattern, and harvesting period of rhubarb? For how many years do the plants stay productive?
A friend has a 30-year old plant that produced well all that time in a location next to a working compost heap.
When she stopped using that site for composting, the plant began producing only small, limp stalks. What should she do?
W.S.
Rhubarb can be planted in spring or fall, the best specific times being March and October. However, potted plants can usually be found later in spring at garden centres. The plants, being perennials, begin pushing up top growth in March in most years, and stalks develop to a useable size in early May.
Harvesting can continue through June, with care to take just a few stalks at a time from each plant. That said, I have heard from gardeners with thriving rhubarb clumps who pull a few stalks in summer without evident setback in the plants.
Rhubarb benefits from a spring mulching with a nourishing compost or/and aged manure. Keep the clumps well watered through the summer 鈥� that is when they are rebuilding their resources for a good crop the following spring.
Thirty years is a long time for a rhubarb plant to continue producing fat, firm, juicy stalks. Your friend鈥檚 plant probably did well for so long because of nutrient and moisture seepage from the compost. In most circumstances, the plants should be dug and divided every five or six years, in March or October, with the growth buds of the divisions set just below the soil surface. With new or newly divided plants, it is best not to harvest in the first year.
Your friend might consider establishing new, purchased plants. Very old clumps have woody crown and root structures that are extremely difficult to dig up. If an unearthing should prove successful, replant only the youngest, outside portions of the old clump.
Dear Helen: What would cause dark speckles on my pampas grass leaves?
A.D.
Pampas grass (Cortaderia) is a large, evergreen ornamental grass that is generally tough, easy-care and problem free. Your plant鈥檚 issue sounds like one of the many leaf spot diseases, possibly Helminthosporium, occurring most commonly in wet conditions in early spring and late fall.
The main remedy is sanitation 鈥� removal of affected leaves, cleaning under and around the plant and then mulching with a聽nourishing compost. Protect yourself against the sharp leaf edges.
鈥� On Saturday, I will be taking a break from writing a column for this holiday weekend 鈥� the garden beckons. Today鈥檚 events cover the period up to my next column on May 23.
Garden Events
Tomato day. The Horticulture Centre of the Pacific, 505 Quayle Rd. in Saanich, is hosting its annual Tomato Day on Saturday, 9 a.m. to noon. Visitors will find organically grown heirloom tomato varieties, as well as vegetable and herb transplants. Free admission to the gardens.
Plant-A-Holics sale. This year's Plant-A-Holics sale on Sunday, from 10 a.m. to 2 p.m. has moved to a new location: Brentwood Bay Nursery, 1395 Benvenuto Ave. It will feature Pacific Coast irises, woodlanders, ferns, succulents, geraniums, hardy fuchsias, roses and plants from Abkhazi Gardens. There is plenty of parking. Cash or cheques only.
View Royal meeting. The View Royal Garden Club will meet on Wed. May 23, at 7:30 p.m. in Wheeley Hall, 500聽Admirals Rd. in Esquimalt. Diane Pierce will discuss and demonstrate how to rejuvenate your garden shrubs. There will be a judged mini show, a sales table and refreshments. Drop-in fee $5.
HCP workshops. The Horticulture Centre of the Pacific is offering the following workshops. To register, call 250-479-6162. hcp.ca.
鈥� The Art of Bonsai: Root Cutting, Sat. May 26, 9 a.m. to noon. Controlling roots with trimming and soil types. HCP members $60, others $70.
鈥� Willow Frame Tray, Sun. May 27, 9:30聽a.m. to 4:30 p.m. Members $120, others $140.
鈥� Healthy soils: Fertilizers and Mulches, Sun. May 27, 10 a.m. to noon. Learn about easily available, natural materials for soil care and nutrition. Members $35, others $40.
鈥� Introduction to Garden Design, Mondays 6:30 to 9 p.m., May 28, June 4, 11, 18, 25 and July 9, 16. Sunday field trips on June 24 and July 8, 9:30 a.m. to noon. The course is designed for the homeowner and those interested in landscape design. Members $250, others聽$295.
