Creeping Thyme to replace a lawn - Ask Extension
Hi, We are thinking of creeping thyme and other plants to cover our front lawn. the area is 2500 sq ft. There is a tree and a concrete path. We are pl...
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Creeping Thyme to replace a lawn #552876
Asked April 12, 2019, 3:44 PM EDT
Hi, We are thinking of creeping thyme and other plants to cover our front lawn. the area is 2500 sq ft. There is a tree and a concrete path. We are planning on placing some boulders and smaller rocks around along with some tall grasses. Any suggestions as to what other ground cover would work well with the creeping thyme?
Do we have to remove all grass?
What do we have to do to prepare the soil?
How long does it take to grow in?
If we leave grass in place can we just dig a hole where we plant to start and will the thyme spread? Or is that what you mean by doesn't compete well with other plants?
What type of watering is best, drip, soaker hose or...?
It says to mulch in winter. What kind of mulch is best? Do you cover the whole plant? How deep? Do we mulch till it takes hold and starts to spread?
To keep down weeds while waiting for it to spread what do I use?
Thank you so much!
Barbara Rowes
Denver County Colorado
Expert Response
Barbara,
I'm going to take each of your questions in turn but, firs,t here's a fact sheet from CSU Extension that addresses retrofitting a yard generally: https://extension.colostate.edu/topic-areas/yard-garden/xeriscaping-retrofit-your-yard-7-234/
1) Yes, you must remove all the turf grass before you plant thyme. You didn't say this, but I am assuming your existing lawn is Kentucky Bluegrass which is the typical turf in Denver. If not removed, KBG will act as a weed in your thyme and because it is rhizomatous, it will spread and take over.
2) Soils in Denver usually tend to be fairly rich in minerals but lacking in nitrogen and either sandy or clay. A good way to figure out what you have, whether you should amend your soil, and with how much is by getting a soil test to start. Here's the link to the CSU Soils lab: http://www.soiltestinglab.colostate.edu/
3) How quickly your thyme fills in depends in part on how closely you plant the individual plants; if you plant them close together (ie. 8" on center), they will cover the space quicker, if you plant them further apart, they will take longer (ie. 18" on center). You have some wiggle room (in school, we used to say 'when do you want impact?!'). It also depends on how quickly they establish and that is dependent on site conditions like soil, exposure, irrigation, etc.
4) No! don't plant the thyme through the turf - unless you know for sure the turf is completely dead and you are just leaving the dead grass in place to avoid erosion. I've seen it done that way but the method has pros and cons.
5) There is no one perfect method of irrigation; they all have pros and cons in terms of cost of installation, water conservation, aesthetics, maintenance, etc. The plants don't care so long as they get the water they need to grow.
If you use drip irrigation, you need enough pipe lines running throughout the space to put an emitter at each plant. If you use microsprays, each microspray will cover a wider area than a drip emitter but you will have the nozzles sticking up around your space and as they get knocked around, you'll need to keep them in alignment. If you use an in-ground irrigation system with pop-up nozzles, you will cover the most square footage with the least amount of heads but it will be the most expensive method to install. You can save a lot of money by just dragging hoses and setting out sprinklers but the hose-dragging method requires some labor and dedication which your schedule may or may not allow.
The one thing I encourage you to remember as you consider your options for irrigation is not to forget about your existing tree. It needs water, too, and its roots snake through the area under its canopy and well beyond. If you turn off the spigot on the area to conserve water, you will also be turning off the spigot for the tree.
6) Mulch can be anything used to suppress weeds and moderate soil temperatures while your new planting still shows a lot of exposed soil. Eventually (ideally), the plants will fill in and mulch themselves. Which mulch you choose is, again, partly budget, partly aesthetics, and partly ease of installation. Wood mulch is readily available at garden centers, big box stores and landscape supply outfits and is pretty easy to spread. It comes in many different colors and textures. It will break down over time and, in the process, compete with your plants for nitrogen, so you will need to compensate with some nitrogen fertilizer if the plants look a little stunted a few years after installation. Stone and gravel mulches are popular and won't break down but they can be back-breaking to install and will raise the heat temperature in your yard. The cheapest mulch is cardboard or newsprint (but it's not much too look at) or the city's free wood mulch give away https://www.denvergov.org/content/denvergov/en/trash-and-recycling/seasonal-programs/mulch-giveaway---compost-sale.html.
Thyme is a woody plant, meaning it does not die down to the roots every winter like an herbaceous perennial but has stems remaining above ground. The reason you've seen advice to cover the entire plant during the winter is because the stems can become desiccated and die off in winter if there is no snow cover or shade. Here in Denver, we tend to have dry winters with intense sunlight and little natural precipitation with spring snow storms.
Your yard's microclimate may or may not fit the general description depending on its exposure (E, W, N, S) and microclimate (the location and size of the tree and the spread of its canopy, what in your neighbors' yards affects your site, etc.)
It's a lot to think about but I hope this has helped; good luck with your project!
I'm going to take each of your questions in turn but, firs,t here's a fact sheet from CSU Extension that addresses retrofitting a yard generally: https://extension.colostate.edu/topic-areas/yard-garden/xeriscaping-retrofit-your-yard-7-234/
1) Yes, you must remove all the turf grass before you plant thyme. You didn't say this, but I am assuming your existing lawn is Kentucky Bluegrass which is the typical turf in Denver. If not removed, KBG will act as a weed in your thyme and because it is rhizomatous, it will spread and take over.
2) Soils in Denver usually tend to be fairly rich in minerals but lacking in nitrogen and either sandy or clay. A good way to figure out what you have, whether you should amend your soil, and with how much is by getting a soil test to start. Here's the link to the CSU Soils lab: http://www.soiltestinglab.colostate.edu/
3) How quickly your thyme fills in depends in part on how closely you plant the individual plants; if you plant them close together (ie. 8" on center), they will cover the space quicker, if you plant them further apart, they will take longer (ie. 18" on center). You have some wiggle room (in school, we used to say 'when do you want impact?!'). It also depends on how quickly they establish and that is dependent on site conditions like soil, exposure, irrigation, etc.
4) No! don't plant the thyme through the turf - unless you know for sure the turf is completely dead and you are just leaving the dead grass in place to avoid erosion. I've seen it done that way but the method has pros and cons.
5) There is no one perfect method of irrigation; they all have pros and cons in terms of cost of installation, water conservation, aesthetics, maintenance, etc. The plants don't care so long as they get the water they need to grow.
If you use drip irrigation, you need enough pipe lines running throughout the space to put an emitter at each plant. If you use microsprays, each microspray will cover a wider area than a drip emitter but you will have the nozzles sticking up around your space and as they get knocked around, you'll need to keep them in alignment. If you use an in-ground irrigation system with pop-up nozzles, you will cover the most square footage with the least amount of heads but it will be the most expensive method to install. You can save a lot of money by just dragging hoses and setting out sprinklers but the hose-dragging method requires some labor and dedication which your schedule may or may not allow.
The one thing I encourage you to remember as you consider your options for irrigation is not to forget about your existing tree. It needs water, too, and its roots snake through the area under its canopy and well beyond. If you turn off the spigot on the area to conserve water, you will also be turning off the spigot for the tree.
6) Mulch can be anything used to suppress weeds and moderate soil temperatures while your new planting still shows a lot of exposed soil. Eventually (ideally), the plants will fill in and mulch themselves. Which mulch you choose is, again, partly budget, partly aesthetics, and partly ease of installation. Wood mulch is readily available at garden centers, big box stores and landscape supply outfits and is pretty easy to spread. It comes in many different colors and textures. It will break down over time and, in the process, compete with your plants for nitrogen, so you will need to compensate with some nitrogen fertilizer if the plants look a little stunted a few years after installation. Stone and gravel mulches are popular and won't break down but they can be back-breaking to install and will raise the heat temperature in your yard. The cheapest mulch is cardboard or newsprint (but it's not much too look at) or the city's free wood mulch give away https://www.denvergov.org/content/denvergov/en/trash-and-recycling/seasonal-programs/mulch-giveaway---compost-sale.html.
Thyme is a woody plant, meaning it does not die down to the roots every winter like an herbaceous perennial but has stems remaining above ground. The reason you've seen advice to cover the entire plant during the winter is because the stems can become desiccated and die off in winter if there is no snow cover or shade. Here in Denver, we tend to have dry winters with intense sunlight and little natural precipitation with spring snow storms.
Your yard's microclimate may or may not fit the general description depending on its exposure (E, W, N, S) and microclimate (the location and size of the tree and the spread of its canopy, what in your neighbors' yards affects your site, etc.)
It's a lot to think about but I hope this has helped; good luck with your project!
Dear Expert!
Thanks so much for your great response. The exposure is west, sorry. I do have a few more questions.
1. You didn't mention soaker hoses. Is that not an acceptable watering method for the thyme and would that suffice for the tree?
2. Since thyme doesn't like competing plants and we would like to plant maybe flox or some other ground cover with the thyme in areas close to the rocks and some natural tall grasses. Are there any that you recommend or that we should not combine with the thyme?
3. Which is better, starting from seeds or is that not a good idea, or transplant?
4. My husband asks :) "obviously there in a huge difference in cost between plants and seeds. Once we get rid of the grass and given time say 3 years will scatter seeding the thyme be successful or would he be better buying plants but planting them 3-4'apart?"
5.Speaking of the tree, we've just moved in and I have no idea what it is. It is pretty tall maybe 35 feet and definitely needs some dead wood trimming. Please take a look at the pics and let me know if you can id it?
Thanks again for your amazing font of knowledge!
Barbara Rowes
1. Soaker hoses - on the plus side, they are inexpensive and malleable; on the minus side, they can distribute water unevenly, crack over time and sometimes feel like you are wrestling a snake.
2. Groundcovers - here is a list from CSU Extension:
https://extension.colostate.edu/topic-areas/yard-garden/ground-cover-plants-7-400/
3. Seeds vs. transplants - seeds would be more difficult because you could face difficult and uneven germination.
4. Spacing - mature thymes are usually 12-18" so spacing small plants (2 1/4" pots) 3-4' apart will leave lots of bare earth which may run to weeds.
5. The tree is a Silver Maple (Acer saccharinum).
2. Groundcovers - here is a list from CSU Extension:
https://extension.colostate.edu/topic-areas/yard-garden/ground-cover-plants-7-400/
3. Seeds vs. transplants - seeds would be more difficult because you could face difficult and uneven germination.
4. Spacing - mature thymes are usually 12-18" so spacing small plants (2 1/4" pots) 3-4' apart will leave lots of bare earth which may run to weeds.
5. The tree is a Silver Maple (Acer saccharinum).
THANK YOU!!!!!!!!!!!
