Finally, the hazy, lazy days of summer have arrived—something many of us longed for during the long, cold and damp spring! The temperatures are warm, the sun is high in the sky, and the rain has fortunately slowed down but is still ample! The heat and humidity have certainly returned too, so try to garden during the cooler temperatures of the early mornings and evenings. Keep records on daily temperatures and rainfall, since summer’s heat and warm nighttime temperatures impact a plant as much as winter’s cold. If you live close to Rutgers Gardens, you can also look at “Rutgers Weather,” which has a summary of the weather conditions in Rutgers Gardens—it is almost like being here! Also, remember to wear a big hat, apply the sunscreen, and drink plenty of water while you garden!
Things to do:
- Weed and fertilize your containers. Water as needed, which is usually once per day. The plants are now beginning to approach their mature size, and it is important to keep them well fed and hydrated. If you used slow release fertilizer pellets in your containers, you may wish to consider a reapplication near month’s end, since most fertilizers only last 2 or 3 months. For heavy feeders, like Brugmansia, you should supplement slow release feed with liquid fertilizer—the slow release granules do not release the nutrients at a sufficient rate to support blooming.
- Some annuals, such as Coleus, Plectranthus, and Persian Shield (Strobilanthes) would benefit from an occasional pinching of the tips, allowing lower buds to break dormancy and grow (as seen at right). This allows the plants to become denser and prevents them from getting straggly or “eating” the neighboring plants.
- Hanging baskets should receive a serious cutback in order to renew the plants for a late-July through September display.
- Irrigate perennial and annual gardens for long periods, ensuring a deep penetration of water into the soil, should rainfall be light during that week.
- For turf grass, raise the cutting height to 3” during these hotter and drier months to reduce plant stress. If you irrigate, as with perennials, do so for extended periods during the early morning to encourage deeper root growth. Try not to water in the evening, since that will promote various fungal problems. Avoid fertilizing turf during July and early August as that will necessitate more irrigation.
- For roses, deadhead, give them a light feeding and remove any leaves from the plant or on the ground that have blackspot, as this will help to reduce future outbreaks.
- Any Japanese Beetles on roses or other plants can be destroyed by flicking them into soapy water.
- Some perennials can be lightly trimmed, such as catnip (Nepeta faassenii) and early blooming salvias (Salvia nemerosa). I leave the dried flowers of yarrow (Achillea) and astilbe on the plant, as they are effective in fall and winter. Early July is the latest time to pinch back unruly Asters and Chrysanthemums, since pinching any later will push bloom time late into the fall.
- Weed and mulch. With the rain and heat, there is an endless growth of weeds this year. It is best to get them young before they become too noticeable or the root systems become too established. Mulch reduces watering and weeds!
- Peas, radishes, lettuce, spinach, and other cool season crops need to be composted and replaced by beans, beets, or any 80-day-to-maturity crop. Thin carrots to roughly 1” apart and beets to 2”.
- At this point summer squash and cucumbers are beginning to come of size; harvest them small (4-6”) and frequently to ensure continued yields and tenderness. If you planted potatoes, they can also be harvested starting in mid-July. A second crop of cucumbers can be planted now to replace those planted earlier that will begin to loose vigor come late August and September.
- Check parsley for Black Swallowtail Butterfly eggs or caterpillars.
- If your zucchini squash get borers early in the season and collapse, and you still wish to grow squash in that location for this year, consider planting some of the scallop squash (patty pan type) for an autumn harvest. They come in solid white, golden, and a combination of white and green striped, which will add color to the Thanksgiving table as well!
- When watering tomatoes, make certain that the fruit remains dry in order to reduce the occurrence of blossom end rot. Keep the tomatoes staked (as seen at right and below). By positioning poles along a row of tomatoes and holding the tomatoes upright between two strings, the fruits can be kept off the ground, air can circulate through the plant (reducing disease risks), and ripening fruit is better seen. A close-up of how the plants are held is pictured below. Contact with the ground can also promote blossom end rot and other decay problems. Yellowing of the lowest leaves on the stems of tomatoes is an indication of Early Blight. It is best to remove these lower leaves, such that there is no contact with the soil, thus the threat in the future.
- Provide a light pruning and training of rampant growing wisteria stems, stray stems of clematis, and other vines. A heavy pruning will invigorate excessive vegetative growth and less flowering buds.
- Prune watersprouts and suckers on small trees and large shrubs before they become too large and begin to deform the plant. With young ornamental or small trees, you may wish to prune off the lowest hanging branches, as they will continue to droop lower and shade out any plantings beneath. Remember, to cut branches back to—but not into—the branch collar at the base of the branch.