What to do this week: Now that we’ve finally had some hard frosts, it’s time to put your garden to bed. Finish planting bulbs this week. This is a great time to take notes and make plans for next spring while you can still remember what your garden did this year. (It’s always changing.) Take photos, too. Cut down perennials selectively. Leave plants standing that have edible seed heads — such as sunflowers and milkweeds — as winter food for the birds, who also appreciate the cover when they dodge hawks. Unhook and drain hoses.
Q. What are Eastham turnips? I’ve heard about them, but when I tried to explain them to my students, I realized I don’t know much. I heard you have to grow them, store them, and then replant them a second year.
A. This year’s Eastham Turnip Festival will be held on Nov. 23, from 1 to 4 p.m. at Nauset Regional High School (100 Cable Road, Eastham). Many locals “turn up,’’ as they like to say, to buy these locally grown heirlooms for their Thanksgiving table. They also celebrate local pride and compete in fun events. The Eastham turnip is a single seed line of open-pollinated turnips, one of several surviving varieties originating in specific New England farm towns. Open-pollinated plants are those that produce seeds that “breed true,’’ meaning they will be very similar to their parents if they are pollinated by themselves or other individuals of the same variety. The resulting seed cannot be copyrighted and is free to all growers who save seeds. Wildflowers are open pollinated, while garden plants and farm crops are often hybrids that resulted from crosses between different varieties to produce a new kind of plant. These do not breed true, so any hybrid seeds must be purchased each year from a commercial source.
There’s also a Gilfeather Turnip Festival each year in Wardsboro, Vt., to celebrate that community’s ancestral turnip variety. One legend says the Eastham turnip originated in Scotland. Another says it’s a natural rutabaga-turnip hybrid.
While many regional American vegetable varieties have vanished, we know this one survived 20th-century industrial farming thanks to one determined Eastham farmer named Arthur Nickerson. He started growing these turnips from local seeds with his dad at age 12 and continued almost until his death at age 93 in 2008. He would laboriously replant the roots after winter storage to produce seeds the second year, as you mentioned in your question.
If you just want to grow the vegetable and not produce seed, you can harvest it in 155 days. But do Eastham turnips really taste better? “They’re delicious, sweet, and you can eat the leaves like kale. Very nutritious. And they grow in sand! They are these great overall vegetables,’’ said former grower Anna Henning.
You can order seeds from the nonprofit Turtle Tree Seed Initiative, 10 White Birch Road, Copake, N.Y. 12516, by mail or phone (800-930-7009). Its catalog (turtletreeseed.org) says Eastham turnips are “not fussy’’ about soil, but old farmer Nickerson used to joke that his turnips tasted better because Eastham had “better sand’’ than other Cape towns. Typical Eastham turnips are white with purple shoulders. “Many times they’re as big as your head,’’ Henning said, “so there’s a lot to work with.’’ Another virtue is that they store well.
Q. I just read your article in the Globe about crape myrtle trees (“Ask the Gardener: With this daisy, you can’t fight city loll,’’ Nov. 3). My crape myrtle tree is probably 10 years old and at least 15 feet tall. I bought it after I saw one while visiting Charleston, S.C. It’s a showstopper. People take pictures all the time. It blooms in late August-September. It’s getting too big, but I worry about cutting it back.
A. After I wrote in my last column that I had never seen a crape myrtle in Massachusetts, I got several e-mails from readers saying they grew or knew of individual crape myrtles on Cape Cod. One wrote that she had spotted a crape myrtle on Washington Street in Newton. Once confined to the Southern states, these colorful Asian trees may be migrating north with global warming; however, breeders also are introducing hardier varieties with DNA from cold-resistant Japanese species. Size and habit range from 2-foot shrubs to 30-foot trees, depending on the variety. You can reduce an overgrown crape myrtle by cutting the stems back to an outward-facing side branch, being careful not to leave a stub. Also cut out dead wood and thin rubbing branches during the winter months when the plant’s architecture is visible. A cold spell can sometimes kill all of the plant that’s aboveground, while still allowing the roots to survive and resprout in the spring.
Send questions and comments, along with your name/initials and community to firstname.lastname@example.org for possible publication. Subscribe to our newsletter at pages.email.bostonglobe.com/AddressSignUp. Follow us on Facebook and Twitter @globehomes.