Swelling on canes of Rugosa rose

14 years ago

I have a 3 year old Rugosa rose that had several swollen areas on the canes on it this year. I pruned them below the swollen area but I am concerned it will just come back. Can I save this rose?

Featured Answer

predfern

14 years ago

Sounds like stem borers or mossy rose gall. Remove canes in the fall.

http://www.extension.umn.edu/distribution/horticulture/components/6594-07.html
Rose Stem Borer

The rose stem borer, Agrilus aurichalceus, damages rose canes when larvae tunnel in a spiral fashion beneath the bark, girdling and killing the canes (figures below). Their presence is indicated when a cane dies above the point of borer tunneling. Leaves on the infected cane turn brown as they die, creating a "flag" among healthy, green-leaved canes. On close observation, a swelling or gall on the infected cane can be seen below the dead tissue, indicating where the borerÂs tunneling occurred. The gall formation weakens canes and it is common to see infected canes broken off by wind. The quickest and most effective control is removal and disposal of infected canes in fall.

From top to bottom: rose stem borer flag, rose stem borer gall, and rose stem borer tunneling.

Mossy Rose Gall

Mossy rose galls are caused by Diplolepis spinosa, a cynipid gall wasp. These galls are common on wild roses of North America, from Ontario to Alberta in Canada and throughout most of the northern United States. They are becoming common on Rugosa cultivars.17 The presence of these insects is indicated by the formation of spherical, golf ball-size, spiny galls on the canes of host plants.

The development of these galls is stimulated in the spring by newly hatched larvae. The galls encase the larvae until adult wasps emerge the following spring. The galls are unsightly and alter the plantÂs shape. They also stress the host plant, behaving like nutrient sinks, drawing nutrients away from the rest of the plant.17, 18 Large numbers of galls on a plant can kill the plant.

Insecticides have no effect on the wasp that causes mossy rose gall. The most effective control is physical removal and disposal of galls in autumn after leaves have dropped and galls are visible. It is important to dispose of all galls since even a single missed gall can produce and reintroduce 30 to 40 mature wasps to the garden the following spring.

Sort by:Oldest

Comments (6)

karl_bapst_rosenut
14 years ago
I have the same condition on some of my rugosas.
Why do you think you are in danger of losing the rose?
I've had this for years with no problems other than the swellings.
I prune below them like you did.
Related Discussions
Pruning Rosa Rugosa Roses, help!
Q
Comments (32)
Rugosa Roses need mostly sunshine in the day. They require little else except good drainage. They don't need to be sprayed (in fact don't like to be) and you can prune them back anytime. Our Rose Society does not recommend pruning this type of rose back to the ground, but you can if you need to it won't kill the bush. They mostly grown between 4-10 ft high. Some can be used as climbers. They can have invasive offshoots if they are not taken out. They are not like the multiflora that are very invasive and sprout up everywhere. Rugosa can be a very good rose for people who want shrubs that bloom all the time with no extra work.Keep them in the sun and they should be fine. There are several varieties that stay about 4-5 ft tall. I have about 15 Rugosa bushes and they make a great hedge for me. They smell is wonderful as I walk down my driveway.
...See More
How to rejuvenate an old rugosa rose?
Q
Comments (7)
I would not remove old growth if it has live bud eyes and shoots growing from it. The bud eyes are small reddish swellings on the canes. Removing the dead wood is beneficial. The bud union is at the base of the plant, where the budded variety is grafted onto the rootstock. Your rose might be grafted, or own root. I would not remove suckers from the area unless you are sure that the suckers are not from your rugosa. Return in early summer to see if the suckers bloom, and compare the foliage and canes to see if the suckers resemble your rugosa. Many of the Cemetery Roses that I visit are in the 50-100 year old range, based upon the age of the headstones, and suckering of the mother plant is common to see. The Cemetery Roses get blackspot, as do garden roses in the area, this is not a concern. If grass or weeds are growing right up to the base of the rose, careful weeding to remove the weeds would be helpful. Some organic fertilizer once or twice a year would be beneficial. If the soil is compact, light raking with a hand rake will help to aerate it. Raking should be done carefully to avoid damaging roots on the surface.
...See More
Pruning older Rugosa roses
Q
Comments (3)
I just saw your post and curious what made you prune so severely in the first place - wanting to control the overall size or was it damage of some kind? And I'm not sure I understand you as you say you cut them "to the ground" but then mention one being 2-1/2 ft. I'm guessing you just pruned low, but didn't remove canes entirely. Generally, rugosas do not need regular pruning other than to remove entirely one or two of the oldest canes (3 yrs or older) every spring to encourage the plant to push new growth. IME rugosas do better with the cane being entirely removed at the ground (literally) rather than shortened. Shortened canes never came back to bloom as well for me as a cane allowed to reach full height and not touched by pruners. YMMV. Anne
...See More
Looking for tips on keeping Rugosa Roses contained/in shape
Q
Comments (5)
I ordered a soil test today, actually! It should arrive in a few days. They have not re-bloomed well at all--they obviously used to thrive, so whatever I can do to get them there I will do. They had a lot of weird yellow bud problems, which some in this forum determined was bud drop, and I decided not to worry about that because the same bushes that had bud drop DID rebloom. Thank you so much for responding. I will keep an eye on the dead looking canes and just remove the ones that don't do much. I don't have any hybrid teas that survived, they are all doc huey now, but I was mostly curious if there was anything I was missing on these. Looks like I'm not.
...See More
carla17
14 years ago
Predfern, I have the cane borer problem pretty bad here. I'm not sure I read how the larvae get in. It's disheartening. I'm gonna use some strong glue on every point of entry I can see. Thanks for the info.

Carla
anntn6b
14 years ago
Several years ago we found swellings down on canes of some rugosas we were watching near a garden with bad Rose Rosette Disease.
I took the canes to a plant pathologist who shared them with several other plant pathologists (You may grin now) and none of them could find the reason for the swelling. There were no insect trails or frass, just ugly swellings.
(This was in northeast TN, close to the KY line.)
We cut all the affected canes off and the disease didn't come back.
Two years later we saw RRD on one cane and the symptoms were very RRD like, FWIW, and didn't have any associated stem swellings.

There are lots of galls that affect different plants. Not all are lethal.
samsthumb
Original Author
14 years ago
I looked at pictures of both of these on the web and mind doesn't look like these. Ann, I have had RRD over the years but I won't really know until the leaves emerge.
michaelg
14 years ago
Carla, the rose stem girdler described in predfern's post is mostly a northern pest, mostly of rugosas, and has no connection with the twig-nesting carpenter bees that you are probably concerned with.

Swelling on canes of Rugosa rose

predfern

Comments (6)

karl_bapst_rosenut

Related Discussions

carla17

anntn6b

samsthumb
Original Author

michaelg

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Swelling on canes of Rugosa rose

predfern

Comments (6)

karl_bapst_rosenut

Related Discussions

carla17

anntn6b

samsthumbOriginal Author

michaelg

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

samsthumb
Original Author