I know the root knot nematodes in Florida love the sandy soil but hate organic matter, but I never thought they would thrive anywhere where it freezes. Yes they probably live in Texas I would assume. But your UN says zone 5 Illinois, are you in Texas or IL?

If you can try to find another place for bonica. If not, I would dig a very large hole and amend it with lots of organic compost and manure. Mulch it heavily with pine needles or any pine based mulch and hope for the best.

Many roses that grow well on their own roots my not be too susceptible to nematodes, but I'm not sure about bonica. I know knock out, Quietness and many ogrs are. Roses grafted on to fortuniana resist nematodes so if you know they are a problem in your area you can get your roses grafted in the future. Otherwise try amending the soil as much as possible and hope for the best.

SoFl Rose,

All of my roses are own root and a lot of organic matter from years of mulching with leaves and straw. I suppose it's remotely possible that it came that way. It never advanced past the one root. I must admit it was the last thing I expected to see.

Hmmm, quite strange right? I know the cold kills them off but maybe, like you say, it came that way from texas. I just wonder if there are lingering nematodes in the spot where you plan on putting your new rose. I don't think there are any pesticides that would work towards removing them. And if you had a cold winter, they should have been delt with by the cold. If Bonica is healthy and has a good root system (free of nematodes) they might not affect her. I'm under the understanding that there needs to be many nematodes in the soil to do a plant harm, and that it takes many years for them to start affecting the plant (4-5 years)

can you take a photo of the root knot so we can take a look?

I wish I had saved it. I went back to the UOI web page. While the southern root knot nematode can not survive freeze temps. The northern and barley root knot nematodes can easily survive. So Bonica shall go to another spot. Wishing now that I would have removed all of the surrounding soil immediately. Wonder how random nematode infections get started?

It also appears I can bake the soil in the oven at 160 degrees for thirty minutes for an effective method of control. I'll just tell DH it's a large batch of brownies.

LOL well good luck. I do think putting Bonica somewhere else is probably a good idea. Maybe you can plant something else in the nematode spot. Something strong and nematode resistant. Good luck.

I have read that French marigolds help to repel nematodes. Perhaps if you plant the French marigolds around your Bonica, the nematodes won't like to hang around there.

I'll try anything at this point as there is some concern that the nematodes could spread. This bed is full of roses.

Patty, the marigolds not only repel but also kill the nematodes. They may help keep the nematodes populations under control.

Karen,

This may be a dumb question but which marigolds would be the French ones?

If you google French marigolds, you will see their pictures. They are the low growing and mounding types that have smaller flowers. Their botanical name is Tagetes patula.

I can't find the memory stick the scans are on (I moved), and the ARS annuals are boxed in the garage, but in the seventies or eighties, there were at least two articles in the American Rose Annuals about the use of ground pine bark cleaning root knot nematodes from the soil. It was used both as an amendment, mixed in the soil as well as a mulch. Previously infected soils and plants were found to be "cleaned" of the infestation simply due to the cleansing action of the pine bark. You might consider using it if it's locally available in your area. You might also search this forum for the scans as I am sure I have posted them within the past two years when the nematode question was raised previously. Good luck.

Oh yeah, i forgot about the french marigolds. They are ridiculously easy to grow from seed (and fast to bloom) so if you can't find them at your local nursery seeds will be the way to go. Also the pine thing Roseseek mentions. Thats why I said to mulch heavily with pine based mulch in the first reply. I should have clarified that pine mulch repels them.