Designing a Native Garden, Part VI: Site Preparation (Lawn Removal, Hardscaping and a Note About Irrigation)
So far on our journey of designing a garden using California native plants, steps one through five have been pretty heavy on the planning end of things. We've barely even touched the soil yet! But now that we have our final planting plan in place and have created our shopping list, it's time to get to work!
The weather is warming up, springweeds plants are flourishing, and dormant grasses (like the nefarious Bermuda grass) are coming back to life in gardens everywhere. With spring in full swing, now is the ideal time to consider removing your lawn to make room for a native plant garden!
If you need a refresher, here are links to steps 1 through 5 in the Designing a Native Garden series:
1: Research
2: Site Analysis
3: Visit Gardens
4: Native Plant Nurseries
5: Create A Planting Plan
Step 6: Site Preparation (Lawn Removal, Hardscaping and Irrigation Advice)
The toughest part of this whole project is this step - especially if you're facing the task of removing your lawn. If your planting site is bare ground, site preparation may be as simple as solarizing the soil before planting. By covering the area in plastic and letting the heat of the sun work, you will kill some (probably not all, but some) of the weed seeds hiding in the soil. If you have a lawn to remove... read on.
Before tackling your lawn, it pays to know your enemy. If you have a soft, green, weed-free lawn of turf grass, sheet mulching or solarization may be all you need to do. Or you can simply dig out your lawn. The goal is to get your planting site down to bare, native mineral soil. But it is imperative to know what type of grass you are dealing with before you begin!
Because if you have something tenacious, like Bermuda grass, your road will be a much longer one.
I am generally opposed to the use of synthetic pesticides and herbicides in the garden (and elsewhere) but Bermuda grass is one battle you just can't fight alone. You can try solarizing, sheet mulching and even digging it out, but you will probably live to regret it. Bermuda grass goes dormant during the cool winter months, so for a time you may think you have won. But it will come back, and with a vengeance! Driving around my town, I have seen many a newly installed drought tolerant garden overgrown with Bermuda grass after only one growing season. A sad sight indeed.
Because Bermuda grass spreads by thick underground rhizomes, it can't really be "pulled" like an ordinary weed. Neither can it be dug out, as the rhizomes extend to a depth of up to ten feet in the soil. Solarizing only kills the top growth, not the powerhouses of stored energy, the rhizomes. No amount of mulch will stop its growth either; I've seen Bermuda grass pop up after being buried under three feet (or more) of soil like it's nothing! And every tiny little piece of rhizome that breaks off will sprout new roots and form a new plant. Rototilling Bermuda is a huge mistake: you will only make it angry. Weed cloth or landscape fabric will not stop Bermuda (and should never, ever be used in a landscape - I have a personal vendetta against the nasty stuff. It's usually made of synthetic fibers and doesn't break down, except to photo-degrade; it does nothing to block the really nasty, tough perennial weeds, like Bermuda grass and nutsedge; and little weed seeds are more than happy to fall on top of the fabric and germinate there. Then, trying to pull weeds that have sent roots and shoots through it makes a terrible mess. Really, save your money and spend it on more organic mulch instead!!)
You can, of course, try all of the above methods of removal. If the patch of Bermuda grass is small (a foot or two in diameter, no more), I would probably try digging it out with a shovel, and then remember to be hyper vigilant around that spot for the next couple of years, removing each new little spout as it appears. This is a good way to prevent an infestation also. Dig it out as soon as you see the first shoot. Don't let it take hold!
For most of us, with Bermuda grass lawns that are well-established, herbicides are the only way to eradicate the grass entirely. Don't misunderstand me: I am not advocating the willy-nilly use of herbicides! Take these chemicals seriously. Use them sparingly, only when needed, and always dilute to the strength instructed on the label. This is important: follow the directions! Don't assume you know best.
To kill Bermuda with glyphosate (Roundup), the grass must be actively green and growing. If it is winter and your grass is dormant, wait for it to green up in the spring. If it is summer and you've let your lawn "die" by not watering it, turn on the sprinklers and bring it back to life (it was never dead to begin with.) In order for the herbicide to reach the rhizomes and kill the plant's energy stores, the top growth of the plant must be actively photosynthesizing, greedily taking in water, sunlight... and your herbicides.
Spraying glyphosate on "dead" or dormant foliage, or on the soil around the plant, will accomplish nothing beyond adding needless chemicals to the environment and wasting your money. So, wait. Patiently nurture your Bermuda grass to a state of healthy, lush green growth before you hit it with herbicide. Then, on a calm day (no wind), read the label on the herbicide bottle, and begin.
The next trick is to wait. Wait for the herbicide to work its way into the roots and rhizomes of the Bermuda grass. After a week or two, when it begins to look "dead," water your lawn again to coax it back to life. You will be amazed at how much green growth pops back up from energy stored in the rhizomes. Once new growth appears, apply a second dose of herbicide. You might even have to repeat this process a third time.
Once you think the Bermuda is finally dead, it's time to physically remove it. This can be done with a shovel (for small areas and the very ambitious) or by renting a sod cutter. (Check your local Home Depot or similar store for rentals.) Do not rototill!!! Sod cutters (and shovels) physically remove the top several inches of sod and underlying soil and roots. Total removal is the goal. Tilling the soil only breaks up pieces of Bermuda grass rhizome, leaving them in the soil to magically regrow. (Trust me, they will regrow.)
Because I can almost guarantee that you will find some living rhizomes once you have removed the sod, get rid of the sod completely! We filled our green city waste bin many times, and took several trips to the dump with loads of rolled up sod. If you leave it anywhere on your property, it will probably regrow. Because Bermuda grass is crazy like that.
If you still see living rhizomes in your soil even after removing all of your sod, water again and try to regrow them. When they grow back, you can decide whether to meticulously dig out the remaining small patches, or to spray the area again. This all may sound like overkill, but being ridiculously thorough and borderline militant in the eradication of Bermuda grass is the only way to get rid of it for good.
Site preparation also includes hardscaping (pouring concrete patios, setting flagstone paths, etc.), contouring the land for drainage (if necessary), placing elements like boulders, and irrigation set up. For details, I will refer you to the book that guided me through this whole process, The California Native Landscape, by Greg Rubin and Lucy Warren.
An important note regarding irrigation:
Drip irrigation, often touted as the solution to our watering woes, is not the answer for drought tolerant native plant gardens. Too often, California natives succumb to the warm, soggy soil created by drip lines after only a few years, earning these hard working plants the unfair reputation of being finicky and short-lived. To properly care for native plants, we must first understand them.
Drought tolerant California native plants from chaparral, sage scrub, oak woodland, grassland and desert communities (generally all but riparian, wetland, montane forest and north coastal forest plant communities) are perfectly adapted to long, hot, dry summers and cool, wet winters. These plants will happily defy all odds to bloom and thrive after receiving no water for six months or more. They tolerate warm, dry soil (summer conditions), and cool, damp soil (winter conditions), but they do not tolerate warm, damp soil, since that combination doesn't exist in our hot, dry Mediterranean climate.
Using drip irrigation during the summer creates the exact conditions drought tolerant natives dislike: warm, moist soil, highly saturated at the root zone. This is a recipe for root rot and disease.
That's not to say that your drought tolerant natives don't need a little extra water during the summer months. While they are still establishing their root systems during their first year, supplemental summer watering is important. And in subsequent years, most natives look a little better when they receive a shower every few weeks (maybe once a month during the summer) to rinse off the dust. (Where some wild natives start to look a little tired and haggard during the lingering heat of August and September, just a little water can help them hold their ornamental value in your garden.)
The key is how you deliver supplemental water to your plants. Ideally, the goal is to mimic nature's rain showers, which wash dust from foliage and slowly percolate through a thick layer of organic mulch. This can be accomplished through low-volume sprinklers or by simply hand watering with a spray nozzle attached to a garden hose, which is probably the best option. Hand watering, though more time consuming, requires that we spend time in the garden, closely examining our plants and adjusting our watering routine to fit their needs. And more time in the garden benefits garden as well as gardener! The plants will tell you what they want. (Remember, a drought tolerant garden of California natives is low-maintenance, not no-maintenance!)
For more in-depth guides on irrigating your native plant garden, visit the California Native Plant Society and Las Pilitas.
Once your site has been stripped down to bare mineral soil and your hardscape features are in place, you are ready to bring in the plants!
The weather is warming up, spring
If you need a refresher, here are links to steps 1 through 5 in the Designing a Native Garden series:
1: Research
2: Site Analysis
3: Visit Gardens
4: Native Plant Nurseries
5: Create A Planting Plan
Step 6: Site Preparation (Lawn Removal, Hardscaping and Irrigation Advice)
The toughest part of this whole project is this step - especially if you're facing the task of removing your lawn. If your planting site is bare ground, site preparation may be as simple as solarizing the soil before planting. By covering the area in plastic and letting the heat of the sun work, you will kill some (probably not all, but some) of the weed seeds hiding in the soil. If you have a lawn to remove... read on.
Before tackling your lawn, it pays to know your enemy. If you have a soft, green, weed-free lawn of turf grass, sheet mulching or solarization may be all you need to do. Or you can simply dig out your lawn. The goal is to get your planting site down to bare, native mineral soil. But it is imperative to know what type of grass you are dealing with before you begin!
Because if you have something tenacious, like Bermuda grass, your road will be a much longer one.
 |
| My garden nemesis: Bermuda grass |
I am generally opposed to the use of synthetic pesticides and herbicides in the garden (and elsewhere) but Bermuda grass is one battle you just can't fight alone. You can try solarizing, sheet mulching and even digging it out, but you will probably live to regret it. Bermuda grass goes dormant during the cool winter months, so for a time you may think you have won. But it will come back, and with a vengeance! Driving around my town, I have seen many a newly installed drought tolerant garden overgrown with Bermuda grass after only one growing season. A sad sight indeed.
Because Bermuda grass spreads by thick underground rhizomes, it can't really be "pulled" like an ordinary weed. Neither can it be dug out, as the rhizomes extend to a depth of up to ten feet in the soil. Solarizing only kills the top growth, not the powerhouses of stored energy, the rhizomes. No amount of mulch will stop its growth either; I've seen Bermuda grass pop up after being buried under three feet (or more) of soil like it's nothing! And every tiny little piece of rhizome that breaks off will sprout new roots and form a new plant. Rototilling Bermuda is a huge mistake: you will only make it angry. Weed cloth or landscape fabric will not stop Bermuda (and should never, ever be used in a landscape - I have a personal vendetta against the nasty stuff. It's usually made of synthetic fibers and doesn't break down, except to photo-degrade; it does nothing to block the really nasty, tough perennial weeds, like Bermuda grass and nutsedge; and little weed seeds are more than happy to fall on top of the fabric and germinate there. Then, trying to pull weeds that have sent roots and shoots through it makes a terrible mess. Really, save your money and spend it on more organic mulch instead!!)
 |
| Perfectly healthy, vigorous rhizomes that were dug up... and promptly began to sprout. |
You can, of course, try all of the above methods of removal. If the patch of Bermuda grass is small (a foot or two in diameter, no more), I would probably try digging it out with a shovel, and then remember to be hyper vigilant around that spot for the next couple of years, removing each new little spout as it appears. This is a good way to prevent an infestation also. Dig it out as soon as you see the first shoot. Don't let it take hold!
 |
| Tilling your soil or lawn only breaks Bermuda grass into little chunks of rhizome... each of which is more than capable of sprouting, growing and spreading to engulf your garden. Just look at that long root!! |
For most of us, with Bermuda grass lawns that are well-established, herbicides are the only way to eradicate the grass entirely. Don't misunderstand me: I am not advocating the willy-nilly use of herbicides! Take these chemicals seriously. Use them sparingly, only when needed, and always dilute to the strength instructed on the label. This is important: follow the directions! Don't assume you know best.
To kill Bermuda with glyphosate (Roundup), the grass must be actively green and growing. If it is winter and your grass is dormant, wait for it to green up in the spring. If it is summer and you've let your lawn "die" by not watering it, turn on the sprinklers and bring it back to life (it was never dead to begin with.) In order for the herbicide to reach the rhizomes and kill the plant's energy stores, the top growth of the plant must be actively photosynthesizing, greedily taking in water, sunlight... and your herbicides.
Spraying glyphosate on "dead" or dormant foliage, or on the soil around the plant, will accomplish nothing beyond adding needless chemicals to the environment and wasting your money. So, wait. Patiently nurture your Bermuda grass to a state of healthy, lush green growth before you hit it with herbicide. Then, on a calm day (no wind), read the label on the herbicide bottle, and begin.
 |
| Part way through the Round-up process (I ran out and had to go buy more...) |
The next trick is to wait. Wait for the herbicide to work its way into the roots and rhizomes of the Bermuda grass. After a week or two, when it begins to look "dead," water your lawn again to coax it back to life. You will be amazed at how much green growth pops back up from energy stored in the rhizomes. Once new growth appears, apply a second dose of herbicide. You might even have to repeat this process a third time.
Once you think the Bermuda is finally dead, it's time to physically remove it. This can be done with a shovel (for small areas and the very ambitious) or by renting a sod cutter. (Check your local Home Depot or similar store for rentals.) Do not rototill!!! Sod cutters (and shovels) physically remove the top several inches of sod and underlying soil and roots. Total removal is the goal. Tilling the soil only breaks up pieces of Bermuda grass rhizome, leaving them in the soil to magically regrow. (Trust me, they will regrow.)
 |
| Look at that lovely dead grass, after the first few passes with the sod cutter |
Because I can almost guarantee that you will find some living rhizomes once you have removed the sod, get rid of the sod completely! We filled our green city waste bin many times, and took several trips to the dump with loads of rolled up sod. If you leave it anywhere on your property, it will probably regrow. Because Bermuda grass is crazy like that.
 |
| Strips of sod rolled up into bundles, ready to be hauled to the dump. |
If you still see living rhizomes in your soil even after removing all of your sod, water again and try to regrow them. When they grow back, you can decide whether to meticulously dig out the remaining small patches, or to spray the area again. This all may sound like overkill, but being ridiculously thorough and borderline militant in the eradication of Bermuda grass is the only way to get rid of it for good.
Site preparation also includes hardscaping (pouring concrete patios, setting flagstone paths, etc.), contouring the land for drainage (if necessary), placing elements like boulders, and irrigation set up. For details, I will refer you to the book that guided me through this whole process, The California Native Landscape, by Greg Rubin and Lucy Warren.
 |
| Boulders in place and irrigation (sprinkler heads) marked with flags. Our gas line is marked with yellow flags. |
An important note regarding irrigation:
Drip irrigation, often touted as the solution to our watering woes, is not the answer for drought tolerant native plant gardens. Too often, California natives succumb to the warm, soggy soil created by drip lines after only a few years, earning these hard working plants the unfair reputation of being finicky and short-lived. To properly care for native plants, we must first understand them.
Drought tolerant California native plants from chaparral, sage scrub, oak woodland, grassland and desert communities (generally all but riparian, wetland, montane forest and north coastal forest plant communities) are perfectly adapted to long, hot, dry summers and cool, wet winters. These plants will happily defy all odds to bloom and thrive after receiving no water for six months or more. They tolerate warm, dry soil (summer conditions), and cool, damp soil (winter conditions), but they do not tolerate warm, damp soil, since that combination doesn't exist in our hot, dry Mediterranean climate.
Using drip irrigation during the summer creates the exact conditions drought tolerant natives dislike: warm, moist soil, highly saturated at the root zone. This is a recipe for root rot and disease.
That's not to say that your drought tolerant natives don't need a little extra water during the summer months. While they are still establishing their root systems during their first year, supplemental summer watering is important. And in subsequent years, most natives look a little better when they receive a shower every few weeks (maybe once a month during the summer) to rinse off the dust. (Where some wild natives start to look a little tired and haggard during the lingering heat of August and September, just a little water can help them hold their ornamental value in your garden.)
The key is how you deliver supplemental water to your plants. Ideally, the goal is to mimic nature's rain showers, which wash dust from foliage and slowly percolate through a thick layer of organic mulch. This can be accomplished through low-volume sprinklers or by simply hand watering with a spray nozzle attached to a garden hose, which is probably the best option. Hand watering, though more time consuming, requires that we spend time in the garden, closely examining our plants and adjusting our watering routine to fit their needs. And more time in the garden benefits garden as well as gardener! The plants will tell you what they want. (Remember, a drought tolerant garden of California natives is low-maintenance, not no-maintenance!)
For more in-depth guides on irrigating your native plant garden, visit the California Native Plant Society and Las Pilitas.
Once your site has been stripped down to bare mineral soil and your hardscape features are in place, you are ready to bring in the plants!
Great article on preparing the garden for native plants!
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