DIY Native lawn redux

I posted in 2015 about how to establish a lawn with native grass seeds. But my results were fairly early. Here I report on how it’s going (well!) and re-summarise my (updated) DIY advice.

In a dry but otherwise mostly mild summer, the lawn browned off (that is, leaves died and it turned a straw-brown colour) until we got a good rainfall in early February. Then the summer-growing grasses (redleg grass* and windmill grass*) immediately put on lots of new, green growth. The winter-growing grasses (weeping grass* and wallaby grass*) put up a little new growth, and new seedheads, too.
*From now on I will put a glossary of correct botanical names at the end of posts. For ease of reading, I’ll use common names (where they are clear) in the main text.

Native grass lawn
Back lawn. Redleg/windmill/wallaby/weeping grass.

So do native grasses give year-round green lawn? Well, you may need to water them in dry weather, but with a bit of water they come good very fast. Mowing? Not much. A couple of times this spring/summer. Given that it was a pretty wet spring, that’s nothing compared to a rygrass/fescue lawn that can go berserk with good spring rain.

dsc_0547
Unwatered couch grass lawn in summer. The dog is not impressed.

Contrast this to unwatered lawn dominated by couch (or “cooch”) grass around here. Couch is also a tough, summer-growing grass. It’s popular in lawns because it spreads well, but gardeners hate it because the mat of runners spreads into gardens and robs them of all their moisture. Prior to rain, it was dying off and mainly tough weeds were growing in this patch in the laneway; I pulled out many of the weeds, but the couch grass had only barely hung in there in many areas such as the one pictured. It might take a while to re-cover the lane! Tough enough to survive, not tough enough to maintain a lawn.

I should point out that patience is a quality you must possess to grow a native lawn. There’s still a few bare patches after 2 years. The patchy grass in the foreground of the first pic above is weeping grass; it is there because through 6-8 months of the year that area is mostly shaded, and other grasses don’t do so well in cool, shady conditions. The bare patches are probably there because its seed is the most expensive and I didn’t sow as thickly as I could have! I’m expecting it will cover the patches over the coming winter/spring, either by spreading or by germination of the seed it’s dropped. The main maintenance is pulling out the occasional weed or unwanted exotic like crab-grass that might have crept in.

Native grass lawn
Front path lawn after 2.5 years: redleg/wallaby grass mix, having received some watering this summer.

Other areas like the front garden path get a bit of water overspray from the adjacent garden beds, so are greener. It’s not a golf-putting green, but it’s holding its own and if you want it green, a single deep watering seems to suffice to green it up for a couple of weeks subsequent (including some quite hot days).

Verdict: Thumbs up! It’s doing well, with little extra water, and infrequent mowing. Now you give it a go!

DIY lawn: step-by-step

I mentioned patience as a necessary quality. Most of the effort of establishing the lawn is preparing the ground, and most of the time is waiting for the seedlings to establish. See the previous article for more detailed explanation of any of these procedures.

First prepare the ground.

  1. If starting from an existing lawn or weedy area, I recommend you remove the top 2cm or so of soil, which takes away weed/grass seeds, excess nutrients (that native grasses generally don’t need), and most of any living plants. Use a sharp hoe, or motorised equipment depending on how large an area you have to work. You may use this soil for making a garden bed, it is probably good quality topsoil.
  2. Dig the soil deeply, either with a rotary hoe/cultivator, or (even better, but hard work) by sinking a spade in as deep as it will go (at least 20cm), lifting out chunks, and turning them upside down. This buries more weed seed and nutrients too deep to affect your grasses. If your soil has been compacted (and it likely has) this also aerates it.
  3. Spread a layer of fine pine bark mulch, not too thick. You can leave it a couple of weeks at this point, killing any weeds that emerge. Then dig the pine bark into the top 10cm or so of soil. This gives the soil better structure and also “reverse fertilises” it (removes nutrients, retarding the growth of vigorous weeds). If your soil is very sandy you could also spread some fine clay at 1-2kg per square metre or so, or use grasses that tolerate sandy soil.
  4. Water it well, and wait! Patience. Let the soil microbiology get started and the soil settle. Pull any weeds you see. Wait for suitable weather for sowing your native grass. You can wait a couple of weeks, months, or longer. The key is to sow your seeds at the best time.

Sow those seed (this is the easy bit).

  1. Decide what grass mix you want. This will depend on where you are, the soil type, the kind of lawn you want, and so on. If you’re not too fussed, cool climates do well with weeping grass and wallaby grass, while areas with hot summers do better with redleg and windmill grasses. A mix of all the above, or one from each category, seems feasible. Other native grass species might do well in your area too – kangaroo grass, mat-grass, and many others; if you can get the seed. If you have mild summers where below 30°C is considered a hot day (Hobart!) get winter-growing grasses for year-round growth. If you live in a hot climate, skip them altogether. I’m happy to make more specific suggestions if you contact me via the comments below. Suggested suppliers were covered in the previous article.
  2. Decide when to sow. Generally, early spring while the soil is still moist, or when it cools down and rains in autumn, are the best times to sow. Summer-growing grasses are probably better off in spring, while winter-growing grasses are probably OK in spring if there’s enough rain, but better in autumn if you’re not sowing summer-growers with them.
  3. Sow that seed! Use a rake, for example to loosen the surface. Or remove a half centimeter of soil from the top and then spread it back over the seed as a top-dressing. Or buy in some sandy top-dressing if you’re really keen. Just make sure the seed are in good contact with the soil, preferably buried shallowly.
  4. Water and wait. Don’t overwater, and don’t fertilise at any time.

And now for patience!

  1. For most grass, keep the soil moist until the seedlings emerge, probably 3 weeks (some dry region grasses might prefer repeated wetting and drying to break their seed dormance, most of those mentioned here don’t have this requirement as far as I can tell). Try not to walk on the area in this time. Don’t overwater! You might drown your germinating seedlings. Moist, not soaked.
  2. You should see seedlings emerge by 3-4 weeks, and if you sowed them well, reasonably thickly. They may appear to stop growing once they have a couple of leaves. Patience! They are probably building up their root area to survive the summer (or, if in cold/cloudy weather, waiting for more sunlight). It could take days or months, but they will make above-ground growth slowly, as conditions are favourable. Some species (eg windmill grass) are faster growing. If the ground dries out, it may shock or even kill them; keep watering deeply, reasonably regularly (if it doesn’t rain).
  3. When the seedlings are clearly growing well, you can ease off the water, but they will still benefit greatly from occasional deep watering through their first summer and any long dry periods. In the wild, native grasses usually establish sporadically and episodically. We are trying to short-circuit that. After they are mostly established is when your water saving starts.
  4. You can mow them as soon as they get over about 5cm, but you don’t have to. Set the mower blades high, at least 3cm if not more. Or let them grow taller (most of these grasses don’t get very tall anyway). Look out for weedy (ie unwanted, probably exotic) grasses that might sneak in on your shoes, the dog, the wind, or perhaps as a minor contaminant of the seed mix you used. It’s easiest to identify them when seed heads/flowers appear. The easiest way is to learn to recognise the native grasses you bought, by their seedheads. Make sure you get it right! You don’t want to discover you’ve been pulling the wrong one and promoting a weed.
  5. You can let them go to seed, harvest some when it’s ripe, and use it to sow another section of native lawn! Or sneak this seed into your nature strip/local park to improve it. I don’t think any of the native grasses I’ve mentioned present a risk of becoming invasive weeds outside their natural range in Australia.

Species’ proper names in this blog post:

  • Redleg grass: Bothriochloa macra
  • Windmill grass: Chloris truncata
  • Wallaby grass: Rytidosperma geniculatum
  • Weeping grass: Microlaena stipoides
  • Couch grass: Cynodon dactylon
  • Kangaroo grass: Themeda triandra
  • Mat-grass: Hemarthria uncinata
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