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iGrow Column: 2014: Year of the Echinacea

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Each year, the National Garden Bureau selects a perennial, annual and edible to become the chosen plants of the year. This year, they have chosen Echinacea, which is a great perennial plant for us to grow here on the Great Plains. It is easy to grow in most of our area because it tolerates drought, heat, wind, cold and tough soils. It generally has few pest problems and offers quite a diversity of plant sizes, flower types, sizes and colors and blooms most of the summer and fall.

Jim Johnson and Gary Larson list three different species of Echinacea in their book “Grassland Plants of South Dakota and the Northern Great Plains,” that are native to South Dakota, Echinacea angustifolia — (Narrow-leaf Echinacea), E. pallida — (Pale Purple Coneflower), and E. purpurea — (Purple Coneflower). They mention that Echinacea was long used as a medicinal plant for treating everything from snake bite to boils and a whole lot more. Various compounds found in Echinacea are still commonly used in many herbal remedies today. They are often browsed by livestock and other animals and can be found throughout the Great Plains from Canada to Texas. They are also a favorite plant of butterflies, bees and other pollinators and also for birds and other animals that like to eat the seeds.

Echinacea prefer to grow in a full sun location, but they can also tolerate some shade. They are usually sold as plants, but you can also grow them from seed. They quickly develop a strong taproot that can penetrate deeply into the soil, providing access to water and nutrients even in poor soils, once established. Generally the native species have pink to lavender flower petals with a dark brown, prickly cone in the center of the flower. The leaves and stems have a rough, bristly texture to them because of the short hairs that cover them.

For many years, most all of the coneflowers available to home gardeners were derived from the typical Echinacea purpurea with cultivars that mainly had pink to purple flowers or white. But there has been a huge resurgence in interest in the coneflowers, so that there are now dozens of different cultivars to choose from that have been developed from a diverse parentage of about 10 different species. Available flower colors now range from white to yellow, pink, orange, pink, purple and red. Plant size ranges from about a foot in height to nearly five feet with a 2-3’ spread. Flowers can also vary by their size, ranging from about 2” to over 5” wide. Some flowers are also double, compared to the typical single flowers with variations in between. The typical central cone may also look more like flower petals now giving the flowers a whole new look.

We have trialed quite a few new cultivars of Echinacea at McCrory Gardens. ‘Cheyenne Spirit” was a new AAS Winner in 2013. You will see plants in this variety with a mixture of flower colors ranging from white to red that bloom freely from seed the first year and look great up until a hard freeze. ‘Firebird’ has bright rose-pink flower petals that droop slightly but produces lots of flowers. ‘Hot Papaya’ was one of our most asked about plants last year with its double-headed flowers and drooping lower flower petals in bright rose red. ‘PowWow™ Wildberry’, which was an AAS Winner in 2010, has bright rose-pink flowers and a compact growth habit. ‘Tiki Torch’ has bright orange flowers and grows about 2’ tall. ‘Tomato Soup’ has large flowers with bright red flower petals.

Echinacea not only light up the garden and attract butterflies, bees and other pollinators, they also make excellent cut flowers. Look for flowers that have just begun to open to just fully opened. These will provide you with the longest vase life, often up to two weeks. Harvesting some of the flowers to be used as cuts in the home can actually stimulate the plant to produce even more flowers. Deadheading, or removing the faded flowers will help too. But, remember that small, seed-eating birds like chickadees and goldfinches love to pick out the seeds in the mature seed heads. So, consider leaving the last flowers of the season on the plants, so that they can mature and provide some winter food. The flower stems and flowers are pretty stiff and durable, so they can also add some interest to the winter garden.

Pests and diseases

We do see a few pest problems with Echinacea at McCrory Gardens and this region. The first is a disease called Aster Yellows. This is an interesting disease caused by a phytoplasma that is usually transmitted by leafhoppers, a tiny insect that sucks sap from the leaves of a wide variety of plants. If it feeds on an infected plant and then feeds on a healthy plant, it may transmit the disease. Once a plant gets the disease, there is no treatment for it other than to pull it out of the garden to reduce the chances of it spreading to other, healthy plants. Infected plants become stunted and yellowish, but their most noticeable symptom shows up in the flowers which can become grossly malformed. Flowers are pale and have a greenish cast and can also develop leafy-like growths in the cone part of the flower. It usually takes a couple years for the plant to finally die, but during that time the disease could spread to many other plants. Aster yellows attacks not just Echinacea but hundreds of other plants and weeds, including other plants in the Aster family but also into unrelated plants like tomatoes, potatoes and even carrots. But here at McCrory Gardens, the most common plant we see this disease in is Echinacea. That is partly due to the fact that we have lots of Echinacea, but it also seems to be attractive to the leafhoppers and pretty susceptible to the disease.

If you see any of these odd-looking flowers, carefully examine all of the Echinacea in your garden, pulling out and destroying any plants that show symptoms. Also look at other closely related plants like Rudbeckia, which seems to also be particularly attractive to the leafhoppers and susceptible to the disease. In some cases, you may notice flowers that are quite pretty and interesting and think you might have found a new flower cultivar. But, chances are you just found a plant with aster yellows and you should pull it out.

Two other diseases are also fairly common, but not usually as damaging. Bacterial leaf spot can cause dark brown to black spots to show up on the leaves and sometimes the stems of the plants. The spots are usually angular in shape because they will often grow along the edge of larger veins. This is a disease that is spread by splashing water, so avoid overhead watering, particularly late in the day when the plants might remain wet for an extended period of time. You can also look for a product that says that it can control bacterial diseases — it will usually contain some sort of copper compound.

Powdery mildew is the other most common disease that we will see in this area. This fungal disease usually shows up in late summer when we get extended periods of high humidity. This fungal disease will be most common on plants that are grown in areas of poor air circulation like under or near trees or close to shrubs and other structures that will obstruct air movement.

The other major pest problem we see is the sunflower head-clipper weevil. This is usually an insect pest of sunflowers, as you might have guessed from the name. But, when it cannot find any sunflowers it will settle for a close relative, like Echinacea or other members of the Aster family. These snout-beetles are fairly small, about ¼-inch long and dark, shiny black. We find them feeding in the flowers, just about the time the flower is ready to open. They feed on pollen and lay eggs in the central cone area. The female chews a ring of holes in the stem, just below the base of the flower. The flower tips over, soon breaks off and falls to the ground. After the eggs hatch, the larvae feed on the flower head, and then crawl into the soil to pupate, overwinter and emerge as an adult the next year. This may be a fairly localized pest however. We have them in some areas of the gardens where there are lots of Echinacea, but do not see very many of them in Echinacea in other garden areas.

If you would like to learn more information about how to identify and grow the native species of Echinacea, take a look at the article by Amanda Bachman at http://bit.ly/1ga8Ztq. Other information on native plants can be found in: Johnson, James R and Gary E. Larson. “Grassland Plants of South Dakota and the Northern Great Plains.” South Dakota Agricultural Experiment Station publication B 566 and Larson, Gary E. and James R. Johnson. “Plants of the Black Hills and Bear Lodge Mountains.” South Dakota Agricultural Experiment Station publication B732. Additional information on Aster Yellows can also be found at http://bit.ly/1fjgWaX. Also go to http://www.ngb.org/ the website of the National Garden Bureau, to learn more about the Year of Echinacea or their other selections for this year, petunia and cucumber.

Is My Seed Still Good?

By Mary Roduner, Extension Horticulture Field Specialist

Calls come in to the Master Gardener hotline every spring with people asking if they can use seed leftover from last year. We are all trying to save money and not be wasteful, so we like to use seed we’ve paid for instead of buying new.

Many seeds can be used for several years if stored properly. For instructions on proper seed storage, access this iGrow article: http://bit.ly/1awfGUp. It includes a chart with the longevity of many popular garden seeds.

To be sure your seed is viable, do a germination test before you order new seed. Materials needed are paper towels, plastic zip-top bags and a marker. For each seed variety, dampen one or two sheets of paper towel. Be sure it is just damp and not wet. If the towel is too wet, the seeds may mold or rot before they have a chance to germinate. Put 10-20 seeds on the towel and fold like an envelope or roll and fold the sides over. Put into the zip-top bag, write the variety on the outside of the bag and place in a dark warm place.

Germination times vary by seed types. What you are looking for in this test is the root emerging from the seed showing it is viable and will grow. This is different from the seedling emerging from the soil and takes several days less. Start checking the seeds in two days and after that every day. Once the seeds begin to germinate, the majority will have root emergence within a week.

Figure the percentage of seeds that germinated and you can then decide how many seeds you will need to plant. For starting seedlings indoors — like cabbage, broccoli, tomatoes and peppers, etc. — this may mean putting two seeds in each cell and using a small scissors to nip off any extra plants. Beans, peas, corn and other plants direct-seeded in the ground can be planted a bit thicker than normal and thin the extra seedlings as normally done.

To explain how well this works, I personally have a large amount of leftover cucumber seed that had been purchased in bulk for a project in 2006. The storage history is spotty at best with the seed being stored at room temperature in a bag for several years before being stored properly starting about year 4. For the 2013 growing season, I did this germination test on about 40 seeds. Every seed germinated. This proved the seed was still viable and there was no need to spend money on new seed.

Looking at the photos, the cucumber seed had root emergence in two days while the nasturtium seed needed five days. As the seed gets older, seed energy goes down and the germination rate also goes down. This is because even though the seed is dormant, it is using tiny amounts of stored energy. Once the stored energy goes below the critical level for an individual variety, the seed will germinate very slowly — taking days longer than fresh seed and the plant will be less vigorous and produce less.

Rosemary seed is a good example of short-term viability. Seed that has not been treated to improve germination has a normal germination rate of 5%. Seed that has been pretreated has a germination rate of approximately 90% for 6 months. After that the viability of the seed goes downhill very rapidly. At the opposite end of this, wheat seed stored in the cool dry environment of the Egyptian pyramids has germinated after 3,000 years. Each type of seed has its own length of viability that determines how long it will store.

So, before you throw out that seed thinking it may be old, do a germination check and you may be pleasantly surprised to find it is still good.