How to restyle plants for fall. Plus advice for pruning hydrangeas, digging up dahlias
The first week of October is a great time to replant, reinvent and restyle your porch and patio planters.
Fall color to replace summer weary annuals is as easy as getting snippy with evergreens such as nandina, cedar and laurel and poking the cut stems of the branches into the moist soil left behind after uprooting your sad looking petunias, marigolds or coleus. Add more color with small pumpkins, gourds or a potted mum or purple aster and you have an autumn look that should last until Thanksgiving.
Q. I am so confused about pruning hydrangeas. Do I cut off the brown blooms of my mop head hydrangeas or leave them on the shrub for winter protection of the buds? — E.G., Email
A. The choice to dead head or not to dead head traditional hydrangea (Hydrangea macrophylla) is up to you. Hydrangeas do not need to be pruned. Some gardeners snip off the dead heads down to the first strong set of beds to make the plant look tidy over winter. Some like the look of the faded blooms, and some claim the dead flowers help protect flower buds.
The old-fashioned big leaf or mop-head hydrangeas flower on two-year-old wood so the branch that bloomed this summer will not flower next year. The important rule is do not do severe pruning in the fall. Wait until March or April to shorten long branches and remove old dead wood.
Don’t panic if you make the wrong cut. Hydrangeas may just flower later in the summer or take a year off from flowering if you (or a helper) cut back too hard in the fall.
Q. I received a fall arrangement, and it included a sedum called “Autumn Joy” with thick stems and lovely rust-colored blooms. When I went to toss out the dead flowers, I noticed roots forming on the stem of the sedums that were in the vase of water. My question is, can I plant these stems with roots into my garden now? — D.C., Bonney Lake
A. Congrats on winning the free plant lottery. You can loosen up the soil in a sunny patch of ground and poke those rooted stems into the ground now and be rewarded with years of blooms from a perennial display of sedum “Autumn Joy.”
Feel free to cut off the flowering head or leave it for the birds, and next spring you should see new growth emerging from the crown of the plant. That is your spring cue to cut back the old stems that you rooted to allow a brand-new sedum plant to grow in your garden.
Q. When do I need to cut back my dahlia plants? This is my first year growing dahlias and I had lots of flowers. Not sure if I need to dig up the tubers now or in the spring. — D.L., Puyallup
A. The time to dig and store dahlia tubers is right after the first hard frost nips the tops of the plants and stops them from producing blooms. Cut the top growth to ground level, then carefully loosen the soil and uproot the potato-like tubers underground. Allow them to dry for a few days in a garage or covered patio before storing them in a paper bag where they will be cool and dry.
If you like visiting Vegas or playing the slot machines, then you may enjoy gambling enough to allow the tubers to stay in the soil. Just cut them back to ground level then cover them with a tarp or sword fern fronds to keep out the rain. If you have planted dahlia tubers in a raised bed, you might just be able to leave them all winter as the good drainage will keep them from rotting.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.
This story was originally published October 4, 2025 at 2:00 AM.