Anything growing in and around your roses will compete for water, nutrients and often light and air circulation, Beth. All plants transpire water (sweat), raising the humidity around them. If you have issues with insects and diseases in your rose beds, adding other plants to compete with the roses can easily exacerbate the problems. Remember, too, "perennials" are often invasive colonizers as are most "ground covers". If they weren't, they'd be considered annuals. Often, insects are drawn to your roses by the "companion plantings". As long as I keep other plants out of where I want to grow the roses, I have very few issues with them. But, that's highly dependent upon your climate and conditions as well as your taste and desires for those areas.

Also, remember when digging holes to add those companions, you're likely damaging rose roots. For budded types, that's a sure fire way to trigger suckers. Really vigorous own root types can also sucker from severed roots. Less vigorous roses may actually be damaged by the root amputations. And, if crown gall is an issue where you are, remember that each cut or scraped root is one more adventitious wound permitting the bacteria an entry point. Kim

Kim, thank you for the advice. However, I heard that that some companion plants if plant at a reasonable distance from the roses to allow good air circulation can help the roses with controlling pests. Monoculture can lead to the quicker spread of pests and diseases. So polyculture which mixes rose garden with other plants and shrubs can create a healthier ecosystem.

- Alliums (onions, chives, shallots, leeks, garlic, etc.) helps repels aphids
- Spearmint repels both ants and aphids
- Geraniums attract pests (Japanese beetles) away from roses
- Petunia is a trap crop for Japanese beetles, aphids...
- Yarrow attracts beneficial insect like ladybugs...

Is this information incorrect? Maybe there are both pros and cons to both monoculture and polyculture depend on each situation?

I have petunia and alyssum between my roses last year and wonder if I shouldn't do that anymore. Thanks Kim.

Yes ma'am, generally polycultures are supposed to be healthier. I can tell you if I plant marigolds ANYWHERE near roses, there will be spider mites. Until I rid the whole garden of marigolds, I had to spray for the mites. Here, petunias have to be sprayed regularly for bud worms which eat the flowers and buds so they have zero color. Alyssum is shallow enough rooted and can be sewn by seed so there is no root disturbance/damage and very little to no competition. When it gets nasty, you pull it up easily and let the self sewn seeds take over.

I'd also read about garlic, etc., helping to repel aphids. I planted society garlic throughout my old garden where it grew wonderfully. So wonderfully, it began crowding out the roses with no visible reduction in aphids. Mints of any kind require a lot more water than most roses in my experience. They also are incredibly invasive, quickly forming massive root systems which are awful to try to eradicate. The only mint I grow is chocolate mint so I can give it the water it demands without drowing anything else and to keep it fully contained in its pot which sits on brick pavers so NO roots touch ANY soil. Only ivy geraniums are low enough to grow among roses without the plants being too tall to grow under the roses. But, at least here, ivies have to be continually whacked as they grow YARDS every summer and can easily climb into fences, bushes and even trees. I've used it as a limited ground cover under a line of Pink Iceberg at a client's house surrounding her patio and monthly I have to clean out the old, dead leaves and other debris in the geraniums. I also pinch them back at the same time to prevent them from becoming too dense and building themselves up into the Icebergs.

If you have enough space between the roses for plants such as yarrow to grow without pushing its way up into the prickly canes of the roses, give them a try. Maintaining the dead flower heads and tired growth of things like yarrow is a royal pain when you have to pull the shards from the rose prickles. Been there and hated every minute of it. At least in my environment, I don't have insect issues growing the roses with enough space for them to get enough air and light. But, I'm probably more arid and hotter than you would be in any bay area. Plus, it's generally breezy here on the ridge top which helps keep the humidity dried out and bugs at bay. Kim

I've been thinking about planting among my roses lately too. What triggered this was when I was weeding and decided to yank out the patch of thyme which had spread quite large. The soil under the thyme was wonderful and moist, much better than the other soil where I'd been weeding. So I was wondering about using a ground cover, possibly alyssum, as mulch. Or maybe even replant thyme.

We will mulch heavily in the next couple of weeks, but a ground cover might work as well. Will be a tough summer for water.

Mulching and "ground cover" are rather conflicting propositions. Ground covers may keep the soil moister during hot weather...IF they aren't so massively rooted they rob all the nutrients and water from the soil. I use the petty spurge weed here as a "ground cover" because it self seeds all over; grows extremely vigorously; pulls easily when and where it isn't wanted; is toxic and gets tall enough to shade new, tender growth from too hot sun and hides it from the blamed "bunnies" who LOVE to eat the basals. The seeds exist in the soil naturally; they blow in on the wind and hitch hike on animals (and people) wandering through. It grows readily in any kind of mulch I put down and knocks itself off in late summer, when it's usually time to renew the mulch, by rusting. Then, I either bury it under new shredded stuff or pull it up and toss it on the weed piles in the paths to break down and keep me from stepping in mud after I water. It isn't "pretty" some of the time but it survives and does the trick. And, it costs me NOTHING.

If you have a nice, dense, thick ground cover and you want to mulch, not only to conserve moisture but to add more organics to the soil as they digest, break down, you either have to pull up the ground cover or bury it. Something annual, like the alyssum, you can simply shake the removed plants over the areas you wish to inoculate with the seeds and it takes care of itself for you. Thyme would either be buried or you would have to replant it. Don't mess with the more invasive herbs such as oregano. That stuff is like a smelly Bermuda Grass. It escaped from one of my raised terraces where I had planted it for cooking and is as much a pest as the Matilija Poppy which escaped from a container I didn't get planted soon enough. Now, that monster is running all over and is due for some herbicide very shortly..

You also have to keep in mind that if you plant anything around or in your rose beds you may want to eat, any and everything you use on your roses will also be in or on what you intend to eat. I had a customer once who grew strawberries as the ground cover under her roses. She complained how oddly they tasted, never thinking the Bayer Systemic and other things she sprayed the roses with were in and on the berries. Some people just don't have a clue about these things. Another, years ago, complained how the Chrysler Imperial rose we sold here in the US wasn't the same she had grown in Israel where she previously lived. There, the petals added the rose water taste and scent to her cooking she enjoyed. Here, they were bitter tasting. I asked her if she was using systemics on the rose. Yup. Whatever you use for the roses will be in the rest of the plants, too. Kim

This post was edited by roseseek on Sun, Mar 9, 14 at 16:40

Very interesting, Roseseek. I've had alyssum over the years and enjoyed it reseeding, then went to vinca which reseeds and shades the ground as well. It has more of a root system than alyssum and is taller. I'll probably get a bag of the alyssum seeds again this year and let the vinca do their thing as well in certain spots.

Kim, thank you for sharing you knowledge and experience. Especially the way you explain why certain things work and others don't. I have learned so much from you and others on this forum.

I read some rose guide books and wish certain sections in those books explain more in details the way you do like why doing something in theory sounds good but doesn't actually work. Keep up the great work. We all appreciate your wisdom and experience ;) Thank you for sharing.

You're more than welcome! I hope I can help you avoid some of the "clean-ups" I've had to endure! Some things can work for a while, then go south on you pretty quickly depending upon climate and conditions where you try them. If your season is shorter, harsher, drier or otherwise not perfectly suited to the "companions" you plant, you may not have as severe result as we do where it's much warmer. But, eventually, if the plants are suited at all to their situations, you're bound to encounter at least some of the issues.

I think the "vinca" socks referred to is the annual "Four O'Clocks" rather than the immortal, invasive vinca major or minor we battle here. Jimofshermanoaks used to lament how he'd battled the vinca minor invading his slope from the property above for over 35 years, until he gave in and quite battling it. The bloody stuff outlived him, unfortunately. Kim