The summer heat has taken its toll on many of our annual and perennial flowers.
With the hot, dry days and attacks by spider mites, grasshoppers and diseases, many beds are sickly to say the least. Although it may not seem like it now, cooler weather and refreshing rains will soon arrive. To help prepare, spend a few moments cleaning up flower beds and giving them an extra boost for a fall burst of color. Here are a few items to add to your weekend "to-do" list.
Start with the annual flowers. This time of year many of the dependable plants are long and leggy with a lot of dead branches. Begin by dead-heading to remove all the spent blooms. Likewise, trim them back by a third or more to encourage new, more compact growth that will bloom in a few weeks. Finish with a light application of a complete water soluble fertilizer and water it in well.
Next, turn your pruning shears to the perennials. Late-season care of these plants is a bit different from the annuals. They benefit from removal of old spent flowers and other dead or diseased plant parts. Keep in mind, though, that self-seeding perennials will not come back if all the seed heads are removed before the seeds have had a chance to drop.
Likewise, do not trim back the plants to encourage a late-season flush of growth. This growth will not bloom again and will be killed by the pending fall frost. Finish with an application of a complete fertilizer. Either water soluble or granular will work fine. Concentrate on fall-blooming perennials, such as mums and hardy asters. Then remember that the next best time to fertilize all the perennials is this fall after the first light freeze has killed the tops.
End with the iris bed. Dividing iris every three to five years will help rejuvenate them and increase flowering. Now is the ideal time to dig, divide and share your iris with gardening friends and neighbors. Since iris clumps are fairly shallow, it is easy to dig up the entire clump. Use a sharp knife to cut the rhizomes apart so that each division includes a fan of leaves and a section of rhizome. The best divisions are made from a double fan that has two small rhizomes attached to a larger one forming a Y-shaped division. The double fans are preferred because they produce more flowers the first year after planting.
Cut the leaves back by two-thirds before replanting. Prepare the soil by removing weeds and fertilizing. Fertilize according to soil test recommendations or by applying a complete fertilizer, such as a 10-10-10, at the rate of 1 pound per 100 square feet. Mix the fertilizer into the soil to a depth of 6 inches. Iris are commonly placed in a triangular pattern using three divisions spaced 10 to 12 inches apart. The fans should face out from the center of the triangle so that the clump doesn't quickly become crowded.