To me, August is the month that epitomizes summer. The days remain long, with the daytime chant of the cicadas with the evening chorus of the crickets. Rainfall in July varied by where you live, but the high temperatures coupled with the generally lower rainfall is showing stress on some plants. August typically has many humid days, but the temperatures are usually in the 80’s, which is good for both the plants and the gardener! Remember to get outside during the cool of the morning or evening, use sunscreen and continue to take good notes of your endeavors.
Things to do:
- Continue to cut the lawn as growth and rainfall permit. Maintain a higher cutting height of 3”+ to reduce the stress on the turf.
- The third and fourth weeks of August are the ideal time for reseeding or seeding new turf areas. The evening dew becomes heavier and helps to ensure proper growth and the warm soils allow proper root development before winter. Supplemental irrigation will be necessary if rainfall is light.
- Make certain plantings from this spring as well as trees planted last year continue to receive weekly irrigation during periods without rainfall. Remember, for a newly installed tree, every inch of caliper size (the diameter of the trunk 6” above the soil) will equate to 1 year of additional care and watering. Hence, a tree with a 3” caliper will require 3 years of additional care.
- Many annuals in containers may begin to look tired. For some, a light pruning with a weekly fertilizing and daily watering will breathe in new life. For others, it is simply time for replacement. For autumn, consider Salvia leucantha (Mexican Bush Sage, pictured at right) and Leonotis leonurus (Lion’s Ear) as alternative options to the garden ‘Mum’.
- Although frost is still 2 months away, at months end you may wish to start taking cuttings of some annuals for rooting, potting and over-wintering for next year’s garden. If your rooting efforts fail, there is still plenty of time to get new cuttings.
- Gather and save seeds of various non-hybrid annuals for seeding next spring.
- The lack of rainfall in some areas has caused some tomatoes to exhibit Blossom End Rot, whereby the base of the tomato turns brown. It is due to a lack of calcium caused by fluctuations in soil moisture. It can be prevented by mulching the plants and giving the soil a deep soaking. The mulch will help prevent fluctuations in soil moisture.
- Bush beans, peas or other crops that have finished producing should be removed, the soil top-dressed with an inch or so of compost, and the area replanted with a crop that will mature within 70 days or by October 15, the average date for frost in NJ. A friend and fellow gardener of mine, Bob Mellert mentioned that the days to maturity on seed packets should be multiplied by 1.5 to account for the slower growth time due to the shortening days as compared to spring. Suggestions for a 2nd crops include:
- Arugula, Spinach, and Lettuce are best seeded out near the end of August when the evening temperatures consistently drop into the 60’s and upper 50’s. These crops will endure the early frosts and the spinach actually becomes sweeter as the temperatures become cooler!
- The length of harvest time for the crops listed above can be extended by erecting low tunnels in October to mitigate any of the earlier frosts. Low tunnels consist of hoops placed about 5’ apart and covered with a fabric like agribon that allows air to pass but protects the plants from early frosts. You may wish to look into making or buying the hoops and the row cover fabric now, so you will not be rushed come October.
- Squash plants may be wilting from squash borer. If so, discard the plant (best placed in garbage to remove the borer and any eggs) and plant one of the crops mentioned above.
- August is the time to get your orders in for planting Garlic this fall!
- Resist the urge to vigorously prune shrubs and trees. Heavy pruning during August and September will result in a vigorous production of new shoots that will not become ‘hardened off’ by the first frost, resulting in not only their death, but potentially the death of the plant! Removal of broken branches or light pruning/shaping is still healthy for the plant.
- Many tree limbs will gradually hang down lower following the flush of new growth. If you did not do this pruning back in July, early August is still a good time. Removing the lowest tier of branches on a shade or small tree during August often makes the Garden look more open and able to ‘breath’ again. It also allows more light to reach the plants or turf grass beneath the tree.
- Late August is an ideal time to plant new perennials, shrubs and evergreens in the garden, as the soil is warm and root growth is rapid!
- Try to keep up with the weeding, especially as the summer bloomers are starting to set seed. Remember, if the plant goes to seed, the average life span of a seed is 7 years and that equates to another 7 years of stooping over to weed!
- Continue to deadhead most perennials, roses and annuals to promote new flowers. For some, such as Echinacea, Silphium and Rudbeckia, you may wish to leave the seed heads, since they are an excellent food source for Goldfinches.
- Cut back the predominantly brown Bearded Iris foliage and inspect for borer damage in the rhizome. If the clump is large and root bound, lift and split the rhizome mass apart such that one fan of foliage has an accompanying 3-4” section of the rhizome or horizontal stem. Set the pieces out in the sun for a few days, allowing the wounds to callous slightly and replant, such that the top half of the rhizome remains exposed and uncovered by soil. August is also the month to separate old Peony clumps. Most Peonies can last 20-30 years before requiring division, so if your plant is still providing ample bloom, no division is necessary! Be careful to leave the growth buds of the Peonies at or near the surface to ensure blossom production. If the buds are planted too deep, the plants will fail to bloom. The peony foliage will wilt following division, but the plant will be perfectly fine come spring.
- Bulb orders should be placed for September or October delivery. If you are interested in any of the autumn blooming Cyclamen, Crocus or Colchicum that are pictured below, early August is the time to place your order for a September delivery!
Mache (like lettuce)
Program Leader in Home and Public Horticulture, NJAES