Questions on: Coneflower/Echinacea

Ron Smith, Horticulturist, NDSU Extension Service

Q: I have a question about purple coneflowers. Why it is called purple coneflower? Is the purple color restricted to the flowers? What other parts have purple or related color shades? (e-mail reference)

A: Purple coneflower is called that because of its flower color. The rest of the plant has green foliage and the seeds are black. This is a good plant for attracting butterflies and naturally spreads through seed drop at the end of the growing season. The roots were and still are harvested for medicinal purposes. Fortunately or not, the purple coneflower has been widely hybridized, so there are many forms and colors available. If the color of the flower is not purple, they are not called purple coneflowers. Instead, the plants are referred to by their hybrid name. I hope this information is what you are looking for.

Q: Can you tell me why the echinacea plants I have in my garden bloom with pale-colored flowers? They appear almost whitish-pink instead of the normal purple. I believe I bought them as purple coneflowers. My garden gets moderate sun and average rain. Do I need to add something to the soil? (e-mail reference)

A: I'm not sure, but it could be a virus that is affecting your plants. The plants may have leaf hoppers who often carry virus diseases to the plants they feed upon. If the plants don't go back to normal color next year, I would suggest getting them out of your garden.

Q: I have purple coneflowers in their second year of blooming. The petals are drying out and turning brown. Could this be a symptom of overwatering? (e-mail reference)

A: Yes, they can get along very nicely on what nature provides because they are prairie plants. They should be fine if you back off on the watering. If anything can kill these plants, too much water will.

Q: I have a coneflower plant in my garden. It has plenty of buds, but they are bent over like they are wilted. Can you tell me what the problem is? We have had a lot of rain lately. (e-mail reference)

A: Vigorous coneflower growth will be hampered if the soil is heavy clay and stays wet after a significant rain event. I lost an entire experimental planting years ago after a 100-year rain event.

Cut a bud back into the stem and examine it for borer activity. These plants can do beautifully left alone in the wild, but begin to have problems when we bring them into our cultured landscape, where we heap too much attention on them.

Q: I am growing purple coneflower in my yard for ornamental purposes and I found there’s an Echinacea Angustifolia and an Echinacea Purpurea. What are the differences between them? Does one flower more prolific? Which is native to North Dakota? (West Fargo, N.D.)

A: There are some nine species of Echinacea in North America. The E. angustifolia is the native; the E. purpurea is the showier of the two, getting a little taller, and is considered more ornamental. Both have medicinal properties and are currently under study at NDSU by yours truly, along with E. pallida, for medicinal constituents. Once established, Echinacea will reseed itself, spreading nicely among other perennials or prairie plantings. The E. purpurea is growing beautifully in my prairie garden at home with no problems, but in our research plots it appears to be vulnerable to aster yellows.

Q: My first question concerns purple cone flowers that seem to have deformed blooms the past two years. Is this aster yellows disease? Should I destroy them and replant? My second inquiry has to do with a local landscaping project I'm working on for my church. I did a soil test. Also I realized when digging for the soil sample the good black dirt on top of the area to be planted is only 8 to10 inches deep with clay below. Our plan was to lay down biodegradable mulch first then plant an assortment of easy care perennials, bushes, and ornamental trees that are drought tolerant with wood chips around all plantings. The "black dirt" soil sample shows organic matter 4.2%, pH 8, Olsen Phosphorus 31, Bray 1 Phosphorus 5, K 121. They recommended using a fertilizer ratio of 15-0-20 / 100 sq ft. Will it work, since we're doing a pretty large area, if as we plant we add black dirt and fertilizer to each area being dug? We planned on adding good soil to all holes dug for the bushes and trees for sure. When adding fertilizer by this method I'm unsure about amounts. (Kandiyohi, Minn.)

A: Unless you know where to get a fertilizer with that analysis, I would opt for what is known as a "garden fertilizer," one that typically has an analysis of 10-10-10, and working it into the soil at a rate of about 10 pounds per 1000 square feet (or 1 pound/100 sf). You shouldn't be so fussy. I know plenty of folks who would be delighted with 8-10 inches of good topsoil! I don't think you will have any problem growing whatever you want. The symptoms with the purple coneflower does sound like aster yellows. I would suggest digging them out.

Q. I'm doing some research on growing and marketing Echinacea and would like to get some information on it. People around here have been digging it up out of the North Dakota prairie and selling it, but I am not sure where they are finding a market for it. Thank you for you help. (Bennett, Colo.)

A. Those that you see digging Echinacea in many cases, are doing so illegally. Price varies of course, with supply, but generally $12 to $15 per pound for quality dried root. We are trying to study national production on a commercial basis to prevent the destruction of both private and public lands across the prairies.

Q. I am interested in planting some Echinacea this spring. If you have any information I would appreciate it. (Ross, N.D.)

A. Echinacea might be better planted in the fall, around mid-October, as it needs a cold stratification period of 90-plus days.

Q. Can you tell me about the purple coneflower? (Ypsilanti, N.D.)

A. The purple coneflower has been around longer than we Americans have been on this continent. Digging it out of the wild destroys native habitat at the current rate it is being carried on.

The reason for the popularity of this beautiful flower is because of its immunostimulant qualities on humans. There are three species currently being studied: Echinacea augustifolia, E. purpurea and E. pallida. The German Commission E (USDA equivalent) has carried on most of the investigative studies to date. NDSU is starting a study this summer on these plants.

Q. Could you please tell me why my purple coneflowers are starting to grow these strange flower buds? I started them all from seed about three years ago and they have done very well.Your column has been very helpful in the past and a must-read for us every Friday. Thanks for your help. (Thief River Falls, Minn.)

A. It has all the symptoms of Aster yellow virus, or something very similar. There is a very good chance that it will outgrow the symptoms next year. There is nothing you can do

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