Virginia Home Grown →

Cool-Weather Plants and First Frost Prep

Tall stems with small, pink 5-petaled flowers grow in a garden.
The cool, moist fall weather initiates a new flush of growth and blooms. (Photo: Peggy Singlemann)

The cooler weather has spurred not only new growth in the garden, but a surge of energy in gardeners! Plants are getting their second wind sporting new growth, which means an increase in flower blossoms and vegetables before the first frost. With the temperatures falling below 90 degrees, tomatoes, peppers and eggplants are producing once again along with other vegetables in the garden. Now is the time to construct a cold frame to extend the growing season for leafy greens, radishes, and other cool-season vegetables. This season extender is easy to construct with old window sashes or even a simple wood frame covered with thick white plastic. There are many DIY styles on the internet to consider, and by adding heat the cold frame can become a warm frame!

White roses are in full blossom
Continue to protect roses from diseases for a few more weeks. (Photo: Peggy Singlemann)

Late September is also the perfect time of year to renovate the lawn by aerating and overseeding with the type of grass suited for the area. Remember to keep your mower blade high so the grass grows thick providing shade to the soil surface. A high cutting blade will easily cut up fallen leaves which will enrich the soil by adding organic matter.

At Maymont, we continue with our regular garden tasks through September and into early October. We spray the roses with a fungicide one more time to suppress the black spot and powdery mildew that thrives in the cool moist fall weather. In the south-facing Italian Garden roses are known to bloom some years until Christmas!

Leaves of invasive plants in different sizes and textures growing through plants in the garden
Fall is a great time to remove the invasive plants that have been growing through your shrubs and borders. (Photo: Peggy Singlemann)

This is the time of year to put extra effort into removing invasive vines and shrubs from the landscape before they set seed. As leaves begin to turn, the different plants that have “volunteered” in the shrubs and borders are easy to spy and remove as well. Remember, woody plants are translocating their carbohydrates from the leaves down into the roots for winter storage. This downward movement within the woody plant makes fall an excellent time in the growing season to control unwanted plants with systemic products. Always carefully apply products and follow the label — it is the law.

Envelope full of dried oblong dark green and light brown seeds
These are some of Peggy's seeds. She recommends placing the dry seeds in an envelope before placing them in the refrigerator. Don't forget to write the plant name and date on the envelope! (Photo: Peggy Singlemann)

In the border, I am still collecting seeds to save in envelopes for next year; when doing so remember to label and store them in the refrigerator. This is also the time to finish the list of plants that need dividing this fall. Mulching the transplants will protect the roots by buffering the soil temperature throughout the winter.

Green flat and spiky Christas cactus vines
Christmas cactus flower buds form in response to day length. (Photo: Peggy Singlemann)

Since day length initiates blooms, I placed the Christmas cactus on my porch a few weeks ago. I will bring it in before the first frost in October. If this slipped your mind, then move the plant out now and when the cold weather forces it back in, place the Brazilian-native plant in a room that has only natural light until flower buds form. Avoid turning a light in that room so as not to disrupt the process.

A potted house plant with large light and dark green leaves is on a porch
Closely examine your houseplants for insects before bringing them inside for the winter. (Photo: Peggy Singlemann)

Over the course of the next month, I will bring the houseplants in from the porch after carefully inspecting them for insects. As the cold temperatures approach, I will dig and dry gladiolus, elephant ear, dahlia, canna, and other tender bulbs before storing them in vermiculite for the winter in a consistently cool space. If growing caladiums dig them while the soil temperature is above 65 degrees, they resent being cold so store them in sand or vermiculite in a place no colder than 50 degrees once they are dry.

Large green tropical leaves
After the first frost, dig up tender bulbs and allow them to dry before storing them in vermiculite in a cool location with good air circulation.  (Photo: Peggy Singlemann)

Finally, trees and shrubs — after reviewing the landscape all season, this is the time to make some changes. Consider creating an outdoor room with hardscaping or screening an unsightly area with evergreens. If you need assistance contact the professionals on the Virginia Society of Landscape Designers website for a consultation with a local designer.

Fall is for planting and for enjoying time in the garden during the cooler weather. Let’s get out and keep growing —remember, gardening is for everyone!

Happy Gardening,
Peggy, Director of Maymont Park Operations and Horticulture