Landscaping in rock - Ask Extension
Hi, I have some landscape rock and some big bushes in front of my house. I would appreciate some advice. The rock is old and the plastic underneath ...
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Landscaping in rock #875290
Asked June 29, 2024, 6:59 PM EDT
Hi, I have some landscape rock and some big bushes in front of my house. I would appreciate some advice. The rock is old and the plastic underneath is not doing much so the weeds are very hard to control. Some questions.
1. we just cut down one of 3 very big bushes - we think it was a common ninebark - and we need to replace it. It was on the sw side of the house. Any recommendations for a low maintenance large shrub?
2. I am guessing this is a no but can we put mulch on top of landscaping rock?
3. Can we plant a ground cover in the rock to help control the weeds? This is on the west side of the building. Any recommendations?
4. we also have landscaping rock under our porch on the east side of the house. Any ideas for a ground cover that we could plant within the rock to prevent the weeds? Any other ideas for that area?
Thanks!
Hennepin County Minnesota
Expert Response
Hello!
1) There are many great shrubs to choose from. And a portion of that choice is driven by the site (size when full grown, sun, soil, etc), and another portion is personal preference. These links below show some possible choices to consider. If you live near the Minnesota Landscape Arboretum, you can see a variety of shrubs growing in that environment to give you some ideas and help guide your decisions too.
https://extension.umn.edu/find-plants/trees-and-shrubs
https://mnhardy.umn.edu/shrubs
2) There’s nothing to say that you can’t put mulch on top of the rock, however, that does cause some difficulties down the road and I wouldn’t recommend it. If you choose to plant more things in these areas in the future, it will be harder to dig through the multiple layers to reach soil. It may also make it more difficult for water and nutrients to reach your shrubs or other plants if the layers are too thick. Wood mulch gradually decomposes over time and so would ultimately form a layer of dirt on top of the rocks. Similarly to your current situation where weeds are now able to grow within dirt and decomposed material that has built up between rocks over time. So some sort of maintenance will be required with any type of mulch.
3/4) There are many options you could consider planting within the rocks. They may help suppress weeds within those areas, but there will still be some weed seeds blowing in between and require some maintenance. I’ve included a link below with some ground cover options. You’d do best to choose plants that can handle the heat that can accumulate within rock mulch. Plants described as being good for rock gardens would be good to consider.
Some individuals choose to treat their rock mulch with a preemergent herbicide. This would be done in the spring before weed seeds start to grow. If you choose to do this, follow the instructions as listed on the packaging. I’ve included some additional resources below for your review.
https://extension.illinois.edu/blogs/good-growing/2021-06-25-disadvantages-landscape-fabric
https://extension.umn.edu/yard-and-garden-news/ground-covers-gardens
https://extension.psu.edu/mulch-a-survey-of-available-options
https://apps.extension.umn.edu/garden/diagnose/weed/idlist.htmlhttps://hort.extension.wisc.edu/articles/early-gems-in-the-rock-garden/
https://apps.extension.umn.edu/garden/diagnose/weed/idlist.html
1) There are many great shrubs to choose from. And a portion of that choice is driven by the site (size when full grown, sun, soil, etc), and another portion is personal preference. These links below show some possible choices to consider. If you live near the Minnesota Landscape Arboretum, you can see a variety of shrubs growing in that environment to give you some ideas and help guide your decisions too.
https://extension.umn.edu/find-plants/trees-and-shrubs
https://mnhardy.umn.edu/shrubs
2) There’s nothing to say that you can’t put mulch on top of the rock, however, that does cause some difficulties down the road and I wouldn’t recommend it. If you choose to plant more things in these areas in the future, it will be harder to dig through the multiple layers to reach soil. It may also make it more difficult for water and nutrients to reach your shrubs or other plants if the layers are too thick. Wood mulch gradually decomposes over time and so would ultimately form a layer of dirt on top of the rocks. Similarly to your current situation where weeds are now able to grow within dirt and decomposed material that has built up between rocks over time. So some sort of maintenance will be required with any type of mulch.
3/4) There are many options you could consider planting within the rocks. They may help suppress weeds within those areas, but there will still be some weed seeds blowing in between and require some maintenance. I’ve included a link below with some ground cover options. You’d do best to choose plants that can handle the heat that can accumulate within rock mulch. Plants described as being good for rock gardens would be good to consider.
Some individuals choose to treat their rock mulch with a preemergent herbicide. This would be done in the spring before weed seeds start to grow. If you choose to do this, follow the instructions as listed on the packaging. I’ve included some additional resources below for your review.
https://extension.illinois.edu/blogs/good-growing/2021-06-25-disadvantages-landscape-fabric
https://extension.umn.edu/yard-and-garden-news/ground-covers-gardens
https://extension.psu.edu/mulch-a-survey-of-available-options
https://apps.extension.umn.edu/garden/diagnose/weed/idlist.htmlhttps://hort.extension.wisc.edu/articles/early-gems-in-the-rock-garden/
https://apps.extension.umn.edu/garden/diagnose/weed/idlist.html
Also, can u pls send some options for small shrubs?
Thank u so much. Can u make suggestions on how to plant the ground cover in the landscape rock? Can I just sprinkle seeds and water them? Do I need to plant them?
Thank u so much. Can u make suggestions on how to plant the ground cover in the landscape rock? Can I just sprinkle seeds and water them? Do I need to plant them?
For planting any ground cover, you will do best to plant within the soil beneath the rock. Because you mention that there is some sort of plastic beneath the rocks, it will be difficult for ground cover to spread on its own in this situation.
For additional guidance on plant selection, there is a great tool that allows you to identify the conditions of the site where you would be planting and size desired, along with other personal preferences, and you will be shown options that could work for you. See here for more information. https://ashs.org/blogpost/1288786/233508/New-plant-selection-program-available-from-U-of-MN
For additional guidance on plant selection, there is a great tool that allows you to identify the conditions of the site where you would be planting and size desired, along with other personal preferences, and you will be shown options that could work for you. See here for more information. https://ashs.org/blogpost/1288786/233508/New-plant-selection-program-available-from-U-of-MN
