Fungus treatment on columbine is a delicate process

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Q. We’ve had a columbine plant for about a year which has been running quite well until the last few months. He has limbs that have started to die off and now he has developed little white spots all over. Please tell me what’s going on and what I can do to save him. It bloomed last spring and looked so pretty. BM, Albuquerque

A. From your description of “little white spots” all over the columbine, I think there’s a fungus among us. Your columbine could be suffering from powdery mildew.

The good news is that powdery mildew, according to my “Organic Gardeners Handbook,” “usually causes poor growth, but rarely kills the plant.”

It is suggested to treat by applying either a lime-sulfur fungicide or Bordeaux mixture. I’m not sure how effective either will be at this time of year, and the Bordeaux blend usually has a temperature restriction for application (never when temperatures are 50 degrees or less) , so consider applying early next spring, just when things are starting to wake up growing and growing. Powdery mildew got a head start this year because of all the wet weather we had in June and July. Mold grows in this kind of weather. Now you see the extreme effects.

You say there are dead and dying branches, so I suggest you take a very sharp pair of scissors and cut those branches off the plant. If they supported last spring’s flowering, they must be eliminated.

Then I suggest that while the leaves are falling this coming dormant period, you put them away and throw them away. If you’re a composter, don’t add these leaves to your pile because mildew would likely grow in a warm, humid place like this. Discard leaves and clippings. Remember we have had an extremely wet late summer and fall period so far. Any mushroom is in its element right now because of the weather.

If the columbine is well mulched, see if you can back the mulch to allow better air circulation around the plant. You’ll want to remove the mulch to help protect the plant while it’s dormant, but for now, a little better air circulation might help remove some of the fungus spores hanging around.

If you need more confirmation as to what is affecting your plant, I would suggest cutting up some extracts, placing them in a zip lock bag, and taking them to a nursery for a consultation.

The “fresher” the collection, the better. Don’t drive for days with the sample on and expect anything to be visible. And please keep the sample closed and contained; you don’t want to risk spreading an infection. Here is a healthier columbine next year.

Q. I’m confused. I seem to recall that you suggest feeding the pansies with a fertilizer that has more nitrogen in its mix. Reading about planting pansies with the bulbs, you tout fertilizers with more phosphorus. What “rule of thumb” am I following? MC, Albuquerque

A. You are correct that pansies will benefit from an application of a fertilizer that has more nitrogen in its mix, but that does happen well in the winter months. For this first fertilization, when you are aiming for a planting of bulbs and pansies, you want to offer a fertilization richer in phosphorus to help rooting. Four to six weeks after planting, you could offer fertilization with a higher nitrogen content in its mix. I like to think of nitrogen as antifreeze. Pansies use nitrogen during our cold periods to continue their growth and, curiously, their flowering. They are special that way.

Since you’re planting again, either apply bulb food or incorporate bone meal into your work. Then weeks later, if you feel the need, offer fertilization with a higher nitrogen base to kick your thoughts in the ass.

It won’t harm the bulbs, and pansies will appreciate your help. Happy to dig.

Tracey Fitzgibbon is a Certified Nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM 87109, or features@abqjournal.com.

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