Your Thoughts Have Turned to Vacation, but Don't Go Until You've Done These Chores

There are several important tasks you should tackle in the garden before you leave for your August vacation.

· Now that blooms have faded on bearded irises, it's time to divide these widely hybridized ornamental perennials. Dividing and replanting now gives roots a head start for winter. When they become too large a mass and need dividing, separate them between the end of July and the middle of August.

There are hybrids of bearded irises that have a genetic tendency to repeat blooming. You might lose the fall flush of flowers on these, but the health of the plant will be greatly enhanced next year.

There are varying theories on how often to divide and transplant. After centuries of breeding irises, it's interesting that there is still no single text offering all the correct practices for growing them. We do know that regular removal of old roots on bearded irises controls the iris borer and fungi.

Bearded hybrids have a distinctive fan of leaves that grow from fleshy, rhizomatous roots. They can appear stunted and stressed in compacted clay soil. When this occurs, replant with one-third compost. They can also become so overgrown that the plants don't flower well. That's when transplanting will make a tremendous difference because this plant is the primary attention-getter of the landscape when in bloom.

Bearded irises grow and bloom from shallow root systems and require good drainage. When you dig them, the soil usually falls off the roots, and they divide rather easily, unless the mass is so dense that you need to cut your way in. Regardless, keep only one-year rhizomes (roots that are attached to the fan of leaves). Dispose of all older root pieces and any showing signs of soft, mushy plant parts. This will keep your irises free of borers and soft rot.

The one-year rhizome for transplanting should be about three to four inches long and must have at least one large fan of leaves attached, but it's fine if there are a couple of smaller fans, as well. Cut the fans in half, to about four inches long, and transplant them to a new location in full sun, making sure the eye or bud on the rhizome is at the soil surface or within half an inch of the surface. Otherwise, it won't flower. Use a generous amount of compost to ensure good drainage.

· Sow your biennials in these next weeks. They are easy plants to grow from seeds. Often misunderstood as short-lived perennials, biennials are defined as plants that bloom a year after they are sown, and then go to seed and die. Sometimes they can be propagated from offshoots that grow from the base of the parent plant, but it is better to grow them from seeds now or buy them as started plants at the garden center in spring.

There is a biennial black-eyed Susan ( Rudbeckia hirta) and a hollyhock ( Alcea rosea). Blue Canterbury bells ( Campanula medium) are a knockout the second year after starting from seed. The biennial dianthus ( D. barbatus) displays some of the most striking colors of the genus.

Check with local garden centers to find biennial seeds. You can also buy them through catalogues. Check Renee's Garden ( http://www.reneesgarden.com, 888-880-7228); Burpee ( http://www.burpee.com, 800-888-1447), and Park Seed ( http://www.parkseed.com, 800-845-3369.)