August Gardening Tips from The Webster Arboretum

August is a period when increased attention to garden maintenance is recommended. Watering, weeding, and mulching are routine tasks that support plant growth and flower beds. During August, weeds tend to grow actively and may produce seeds. Gardens with more weeds can attract insects, increase the risk of disease, and provide cover for animals such as voles. Weeding during this time helps reduce competition between weeds and plants for sunlight, water, and nutrients, and limits seed production for future weed control.

Watering in August helps plants cope with higher temperatures and drier conditions. Maintaining consistent moisture levels can minimize wilting, leaf damage, and reduced flowering or fruiting. Deep watering supports strong root development, which may improve resilience to heat. Newly planted trees and shrubs benefit from regular and thorough watering during periods of hot, dry weather, with deep soaking recommended at least once per week.

Now is a suitable time to inspect mulch levels and replenish if necessary. Mulch serves as a barrier that reduces evaporation and promotes soil moisture retention, which is important during periods of hot, dry weather. It can also inhibit weed growth by limiting sunlight exposure to weed seeds in the soil, and it insulates the soil, helping to keep it cooler and reduce stress on plant roots.

Annual plants are available on sale at many garden stores and may be used for fall color in any empty spaces. Continue removing dead flower heads from existing plants; this practice encourages additional blooms and prevents seed development, which may otherwise divert energy from the plants. For summer growth, pinch back flowering herbs before they go to seed, and consider preserving them by drying or saving for use during winter.

If you have not already done so, remove dead foliage from daffodils, tulips, and other spring-blooming bulbs. Dividing bulbs may be considered at this time. While dividing is not necessary every year, it is typically recommended when the plant produces fewer blooms than in previous seasons or becomes overcrowded. Bulbs generally require division every three to five years. To divide, carefully dig up a clump of bulbs, separate them, and replant as needed to propagate new plants or manage overcrowding. Use a garden fork or a hand trowel to dig several inches out from the plant to avoid causing damage. Gently lift the bulbs out from beneath, aiming to separate them without injury and provide the new divisions with a suitable start in their new locations. Using your hands, gently pull the smaller bulbs apart from the main bulb. Discard any bulbs that are diseased, soft, or show signs of pest damage, retaining only those that are firm and healthy.

Tender bulbs, like gladiolus, need to be dug up and stored for the winter. In late summer, but before the first frost, gently dig up your gladiolus plants. Gladiolus look a little different than tulips or daffodils because they grow from small bulbs called corms. Upon lifting, you may find that the corms have new tiny corms attached around the base. In addition, Gladiolus form a new corm on top of last year's old one. So, you'll spot a dried-out corm below the one from which your Gladiolus is growing.

Carefully remove any excess soil from the corms by gently shaking or brushing them. Trim the foliage and flower spike to approximately one to two inches above the corm. The curing process should then be initiated by placing the corms in a cardboard box or on a tray lined with paper to provide an optimal surface.

Arrange the gladiolus corms on the curing surface, ensuring ample space between each bulb to promote adequate airflow. Leave them uncovered in a shallow box or tray, positioned in a dry, well-ventilated area that maintains temperatures between 35°F and 60°F and is not subject to freezing.

After the corms have thoroughly dried, remove and discard last season's desiccated corms, located at the base of the new growth. Separation can typically be achieved by hand; however, a clean knife or pair of scissors may be used if necessary. Inspect for and gently detach any new, small corms from the base. It is also essential to examine all bulbs for signs of rot or soft, unhealthy spots and to discard any that are compromised.

For storage, place fresh newspaper or parchment into the box or tray and return the healthy bulbs to their storage environment. Alternatively, consider using paper or mesh bags to keep the corms separate, as it is critical that the corms remain dry and do not come into direct contact with one another. Maintain storage temperatures between 35°F and 45°F for best results.