Zoysia is one of the favourite grass seed types for Australian lawns. It’s dense and soft with a lovely green colour that is nice to look at, and, when established properly, it is drought and heat tolerant and can happily withstand heavy foot traffic.
Zoysia has a high silica content which means that the longer the blade of grass is allowed to grow, the stronger it becomes. As such, healthy zoysia lawns are typically kept at a height of about 3 to 5 centimetres. This is what makes it so comfy to sit, lay and play on.
When mowing zoysia it’s important not to trim any more than 1/3 of the blade length off of the grass. So, if your lawn is at 6cm tall, only trim it to 4cm. In summer months it’s a good idea to keep your grass length a bit longer – this will keep your lawn healthier.
Zoysia tends not to need as much mowing as some other grass varieties, giving you more time to spend enjoying the lawn instead of mowing it. Depending on how much water, sunlight, and fertiliser it gets, you’re probably looking at once a week to once a fortnight for mowing.
Dethatching is critical for keeping your zoysia lawn healthy. Thatch is the term given to the layer of partially decomposed plant material which builds up on the soil surface. Zoysia is prone to thatch build up because of its tough stem.
Thatch can prevent sun, nutrients, and water from making it into the soil, depriving the lawn of these essentials. Whenever you notice thatch building up, remove it with a dethatcher or rake. Mowing with a bagger can prevent it accumulating so quickly.
Zoysia is very drought resistant and doesn’t need much watering. If you’re in an area with reasonable rainfall you mightn’t even need to water your lawn. Usually, a zoysia lawn will need about 2cm per week for good growth.
It’s best to only water zoysia when there’s signs that it needs it. To check if the lawn needs watering, look at the leaf blades. If they’re curling inwards, give the lawn a water.
Like water, zoysia doesn’t need much fertilising. Fertilising when not needed won’t benefit your lawn, it’ll just promote thatch, be more difficult to mow, and need mowing more frequently.
The best type of fertiliser for zoysia is a slow release granular fertiliser with a 3-1-2 N-P-K ratio. That means 3 parts nitrogen to 1 part phosphorus to 2 parts potassium. Fertilise once every 4 to 6 weeks in the growing season (summer) for up to 4 applications. That should be plenty.
It’s important not to fertilise in winter. This might encourage your lawn to break its dormant spell which will make it very vulnerable to any subsequent freezing temperatures.
Pests and Weeds
Zoysia isn’t a grass that’s often overrun by weeds and pests. Sometimes it may succumb to some dollar spot or insect infestation, but these are usually easily brought to bay with some simply applied treatment. If you see signs of infestation, get it diagnosed and apply the appropriate treatment.
The most important thing to remember when applying herbicide or pesticide to a zoysia lawn is to only ever use products which are approved for use on zoysia, or you may find yourself with no lawn left.
The dense covering of zoysia means that it tends to keep weeds under control all by itself. Never use herbicide before planting zoysia or while it is still establishing itself – it may not be strong enough to handle it.
Applying a herbicide in autumn and early spring can sort out any weeds that might potentially be a problem.
Care Over Winter
Arguably the biggest drawback of zoysia is that it browns off during the winter months and goes dormant. There really is no cure for this, and it needs to be taken into consideration before you select zoysia as the lawn seed for you.
The best thing you can do to maintain a healthy zoysia lawn over winter is to overseed and use a cold weather grass type for the winter months. The cold weather grass (usually tall fescue) will spring to life in winter and let the zoysia rest, only to go dormant in summer when your zoysia comes back to life.