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  • Upcoming events in Middle Tennessee

     

    Save the Date: Perennial Plant Society’s 30th Plant Sale is April 4, 2020, 9 a.m. – 1 p.m. at the new Expo 3 Building at The Fairgrounds Nashville. Here’s where you can find the newest varieties of perennials, shrubs, vines and annuals from local growers, along with long-time, never-fail favorites, ready for spring planting. Learn more at the PPS website.

     

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Longer life for poinsettias

Question: How long do poinsettias last? The plant I brought home early in December still looks nice, and I hate to throw it out. Will it keep growing?

poinsettiaThe length of a poinsettia’s life generally depends on how much care you’re willing to give it. Some people bring it home to display for a few days, and without any attention at all it dries out and begins to drop its leaves within a couple of weeks.

If yours is still doing well, you’ve given it at least the minimum amount of TLC: indirect light in a room that’s not too warm, enough water to keep the soil moist but not soggy. If you continue to care for it, the plant should last well beyond the holidays. Continue reading

Plant pansies for fall and winter color

I would like to have pansies in my garden this fall and winter. Is it better to plant them in pots or in the ground?

Pansies 2Pansies can be a pretty addition to the landscape in the fall, either in garden beds or in containers. They’re easy to care for and won’t wither and die when the temperature drops – in fact, they thrive in cool weather.

You can grow pansies from seed, but it’s easier to start with transplants, which are available in nurseries and garden centers everywhere around the region right now. Start with plants that are compact and healthy (if they are already leggy and shaggy, they may never look as nice as you’d wish).

To plant in containers, use a good potting mix and make sure there is adequate drainage (experts at Organic Gardening suggest using a newspaper or paper towel layer over the drainage holes, rather than pot shards or gravel, to keep soil from washing out). Plant densely, and water the plants thoroughly.

In garden beds, proceed with the planting of pansies as you would any other annual: Prepare the garden bed, adding compost or other organic material so that the soil drains well. Space the transplants closely (garden expert Judy Lowe suggests placing them 4 inches apart) and firm the soil around the plants so they won’t be lifted out of the ground as the soil freezes and thaws. Water thoroughly, and add a layer of mulch. Fertilize weekly until frost with a product made for flowering plants.

Pansies grow best in full sun but can tolerate partial shade.

Pansies may begin to look scrappy during the coldest part of winter, but they likely will spring back to life when the weather begins to warm up again. Enjoy them for a while longer in spring, and be prepared to replace them as things heat up. Pansies do not grow well in the summer heat.

Poppies next spring

I saw beautiful poppies in gardens this spring and summer and would like to grow some of my own. When and how do you plant them?

There are several types of poppies; some are perennials, some are cool-season annuals. A few of them can be grown from seed sown in the fall, so start planning now to have a garden of poppies next year. Here’s a short list of the possibilities, according to the editors of the Southern Living Garden Book:

Iceland poppy (Papaver nudicaule) is a short-lived perennial with cup-shaped blooms of yellow, orange, salmon, pink, white or cream. Sow seeds or set out transplants in the fall.

Oriental poppy (P. orientale) has large, crinkled blooms in scarlet, orange, pink, salmon or white that grow from bushy clumps of foliage. The blooms may be black at the base. Plant dormant roots in the fall.

Shirley poppy, or Flanders Field poppy (P. rhoeas) is an annual poppy with single or double flowers in white, pink, salmon, red, scarlet, lilac or blue. Sow in the fall by mixing seeds with an equal amount of sand and broadcast it where you want them to grow. Note: The Southern Living Garden Book says this is a “notorious self-sower,” which is usually a gentle way to say it could take over your garden whether you want it to or not.

Alpine poppy (P. alpinum) is a perennial that grows better in fast-draining, gritty soil. It has smaller flowers (1 ½ to 2 inches in white, yellow, orange or salmon. It, too, self-sows freely. Sow seeds in fall or early spring.

To plant poppy seeds, prepare the soil in a bed in full sun and simply scatter the seeds on top, or barely cover the seeds. Water the ground carefully, and kept the area moist throughout the fall.

 

Prevent powdery mildew

QUESTION: How do I keep my beautiful zinnias from getting powdery mildew? It may be too late for this year, but what should I do different next year?

Powdery mildew is a fungus that thrives when nights are moderately cool and foliage stays damp. It travels by airborne spores, and appears as gray or white splotches on leaves, stems and flowers of susceptible plants, such as zinnias. A mild case is merely unattractive; a severe case of powdery mildew can cause distorted shoots and leaves, misshapen flowers or can prevent flowering altogether.

The best defense is to give zinnias room to grow without crowding, which allows air to circulate better around the plants, and water only in the morning, so the foliage has time to dry before nightfall. Cut back on the use of high-nitrogen fertilizer, which produces succulent new growth that is a major powdery mildew magnet. Grow them in full sun; hot temperatures (above 90 degrees) inhibit the growth of mildew.

There are fungicides available that should be applied as soon as you begin to spot the mildew (so yes, probably too late for this year), but I always suggest trying the good-cultural-practices method first. The University of Tennessee Extension has a short list in a publication about powdery mildew here. If you decide to go that route, be sure to read and follow directions on the product label.

Zinnias are not the only things plagued by powdery mildew. Lilacs, roses, crepe myrtles and other woody ornamentals, and many herbaceous ornamentals and bedding plants are also targets when weather conditions favor the fungus.

 

Garden seeds: How old is too old?

QUESTION: How long do seeds last? If a seed packet says “purchase by 12/11,” would the seeds still be good for this year?  I’m looking at sunflowers, green beans, and other summer vegetables.

Packed for 2011. Still good? Probably, if they’ve been kept dry and cool.

It’s probably a common experience among gardeners to find packets of last year’s seeds – or seeds from two or more years ago (opened or unopened) stashed in a forgotten corner. They look too good to throw away, but is it worth wasting time and space in the garden to plant them if they may not germinate?

The good news is that many seeds last beyond the “sell-by” or “packaged for” date that’s printed on the packet, especially if they’ve been kept in favorable conditions – dry and reasonably cool. Seeds of parsnips, onions and leeks are among those that will only be good for a year, but seeds of most of the common garden vegetables can last two, three, or some, even five years. Here’s a short list from vegetable researchers atOregonStateUniversity:

Two years: sweet corn, lettuce, parsley, peppers, chard.

Three years: Bush and pole beans, carrots, cucumbers, melons, peas, squashes, tomatoes.

Four years: radishes, turnips.

Seeds of annual flowers are generally good for 1 – 3 years, the researchers say; seeds of perennials can last 2 – 4 years.

You can test the viability of a packet of seeds by placing a few in a moist paper towel in a warm room for a few days to see if they germinate. Seed Savers Exchange provides detailed instructions here.

If you have seeds left at the end of the season, the best way to store them is in a sealed jar with something to absorb moisture (rice or powdered milk are two suggestions). Store the jar in the refrigerator or a cool area in the house, such as a basement.

 

Sweet surprise: sweet potato vines

QUESTION: The ornamental sweet potato vines I grew in large pots last summer produced potatoes – to my surprise! Can they be replanted to produce vines next year?

Sweet potato vine (Ipomoea batatas) ‘Blackie’

Yes! The sweet potatoes that are grown for their ornamental vines don’t have much taste, but U.T. Extension agent David Cook says you can save the tubers to produce the same foliage next year. Here’s how to do it:

If the potatoes haven’t already frozen (and by now, you may find that they have, unfortunately), dig them up and store them packed in straw in a dry, cool place. When the weather begins to get warm again, the tubers may begin to sprout. Cut them into sections just as you would cut a seed potato, with at last one “eye” per section. Allow them to dry for a few days, and plant them in the ground after the frost date has passed (mid-April here in Middle Tennessee).

Ornamental sweet potato vines come in a variety of fancy-leafed “flavors.” ‘Blackie’ is an easy-to-find favorite, with purplish-black, deeply lobed leaves. ‘Ace of spades’ has heart-shaped leaves. ‘Tri-color’ is variegated with green, white and pink foliage, and the variety called ‘Marguerite’ has golden-green leaves.

The vines grow fast, and are a striking addition as a “spiller” in a container, draping elegantly over the sides. I learned last summer that rabbits find the leaves tasty. If your garden has a resident rabbit (as mine does), you’ll find the vines will start to disappear, so be warned.