Q. I notice primroses blooming all over this spring. Are they easy to grow? – D.I., Cushing

A. Indeed, they are! Primroses prefer to grow in partial shade, in cool moist areas. They enjoy rich soil, too, so amending any garden soil with additional rich organic matter, compost or composted manure is recommended.

Primroses are relatively easy to grow from seed. One may readily germinate these hardy perennials in spring or early summer, growing them on through the summer months and allowing them to establish a growing space in the garden. The hardiest primroses most easily germinate in about three to six weeks at around 68 degrees F. Freshly ripened seed harvested from recently-flowered plants tends to perform best.

New plants may also be propagated by dividing older primroses. Division should take place after flowering has finished. Be sure to cut away spent blooms to ease re-establishment of new plants.

Q. How often should irises be divided? – M.K., Waldo

A. When the partially underground stems of iris plants become crowded, it’s time to divide iris plants – typically this means dividing plants every four or five years. Naturally, if the plants are growing under less-than-ideal conditions, the plants may require division less often.

To determine if plants should be divided, closely examine the bulbous rhizomes at the base of the iris foliage. If overcrowding prevails, or if any darkened, rotting tissue is spotted, division is overdue. After flowering, cut away the seed heads and dig up the iris. Separate each “fan” of leaves from the mass of plants. Replant each new plant at the same depth at which it formerly grew – making sure to expose a bit of the rhizome to the air and making sure to carefully and completely bury the feeding roots. Cut the leaves back to 6 inches to ease the shock of transplanting.

Q. My garden is really showy by the middle of summer, but I don’t have very much flowering in early spring. Can you please list some perennials that bloom in early spring? – M.W., Ellsworth

A. Certainly! Some of the showiest spring-blooming perennials include rockcress, sweet William, creeping phlox, cushion spurge, Virginia bluebells, catmint, basket-of-gold allysum, marsh marigold, candytuft, ajuga, dame’s rocket, cranesbill, pheasant-eyed pinks, leopard’s bane and thrift.

Q. I am interested in purchasing some biological organisms to help control pests in my garden. Do you know of any good sources for information about beneficial insects, etc.? – E.S., Hampden

A. A free publication from the California Department of Pesticide regulation is available at 1020 N. St., Room 161, Sacramento, CA 95814-5604 and also online at http://www.cdpr.ca.gov/docs/dprdocs/goodbug/oganism.htm. One may purchase biological controls from many companies, including: Gempler’s P.O. Box 270 Mt. Horeb, WI 53527 (phone 800-382-8473); BioQuip Products 17803 LaSalle Ave., Gardena, CA 90248-3602 (phone 310-324-0602); Great Lakes IPM, 10220 Church Road, NE, Vestaburg, MI 48891 (phone 517-268-5693).

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, 512 North Ridge Road, Montville 04941 or e-mail dianagc@midcoast.com. Selected questions will be answered in future columns. Include name, address and telephone number.