By Todd Layt
Nara™ native turf, gardens and patio pots can all suffer in our hot Australian summers. Over the years, I have learnt some interesting ways to help get lawns and plants through summer. I have also found some clever techniques to help reduce the work load. Some tips are simply good horticultural practice, whilst others are a little more creative.
The Best Lawn Types
Apart from getting a tougher lawn type, which is usually not an option, there are many techniques that can help get lawns through summer with less damage. Firstly, try raising the lawns mowing height. The theory is that the lawn will handle summer and dryer times more easily. The lawn will become healthier, more robust, and some claim the root system will grow deeper.
Personally, I find this mainly true, but with one proviso; I like to mow my lawn shorter in early spring to help reduce thatch and let it get a little longer as summer approaches. I find this particularly important with a Buffalo lawn. The better varieties of Buffalo grass have superb drought resistance, and a raised summer mowing height helps this (by drought resistant, we mean they take longer to brown off). I find Palmetto® Buffalo grass has very good drought resistance. Some types of Buffalo grass, however, have very poor drought resistance, so be careful when assuming you are maintaining a Buffalo lawn with good drought resistance.
Turf varieties such as Couch, Empire™ Zoysia and Nara™ native turf have incredible drought tolerance, meaning they will survive long periods of severe drought, but they will brown off before the good Buffalo grass varieties. If a bad summer sees massive water restrictions and no rain for 2 to 3 months, provided the soil was not extremely sandy, the Couch, Empire™ Zoysia and Nara™ turf will survive and green up when it rains. Of the Buffalo types, only Palmetto® Buffalo grass has proven it can do this.
Palmetto® turf has survived for many years on Windsor road in Western Sydney with just natural rainfall through periods just like this. Under severe drought stress, some Buffalo lawn types simply die. The biggest problem with Couch of course is its aggressiveness at running into gardens, its poor shade tolerance and the fact that weeds invade it very easily. Empire™ turf and Nara™ native turf have none of these problems, although Palmetto® turf has better winter colour than Empire™ turf. You'll find that Empire™ turf and Nara™ turf need slightly less mowing.
Kikuyu has the same invasive problems of Couch, although even worse. It is not as drought tolerant as Couch, Empire™ Zoysia and Nara™ native turf, and not quite as drought resistant as the better Buffalo grasses. Cool season grasses should be avoided all over Australia, except maybe Tasmania. Our hot summers, drought condition and water restriction are making them impossible to keep alive. Fescues, Rye grass, Blue grass etc. are on borrowed time in this country.
Summer Maintenance Tips For Lawns
Now that I have explained the differences between the turf types, I can provide some more summer maintenance tips. With Buffalo grass or Kikuyu, try to avoid letting them dry out completely. Sure, they can go brown and come back, but even a little water after 2 weeks of summer dry can have a benefit. If you cannot water due to water restrictions, then apart from praying for rain, the following may help.
As I said earlier, a little more length of leaf can really help these turf types. If the lawn is really dry, and unless it is really long, avoid mowing it, particularly do not mow it short. I know many will say "but I get paid for mowing it". Well, imagine hurting the lawn because of your short mowing, only to find that the damaged lawn will now not need mowing for many weeks to come. If you have to mow it to keep a schedule, simply take hardly any clippings, just tip it. Avoid high nitrogen fertiliser applications during or just before summer.
While water restirictions are in place, unless the soil is very sandy, fertilise in early spring and autumn only. When your client can water, encourage them to water at most once per week in summer, but make the waters long and heavy. This encourages a deeper root system. The advice is pretty much the same for Couch, Empire™ Zoysia and Nara™ native turf apart from the fact that you really need to watch Couch and Kikuyu along garden borders or paths. In the summer months, these grasses can run 30 to 50 centre metres into a garden within 3 weeks.
In summer, edge these lawn types every week. If they do get into the garden, Fusilade will kill the grass without hurting plants, provided the plants are not true ornamental grasses; this chemical after all is a grass killer. Grass like plants, such as Dianellas, Lomandras and Liriopes can be sprayed with Fusilade and will be ok as they are not true grasses. Buffalo grass, Empire™ Zoysia and Nara™ turf need less edging.
Summer also means too much mowing, particularly if it has rained a lot or if you are lucky enough to be able to water. One way of reducing mowing is to use Primo Maxx. Once this has been applied, it can reduce the amount of mowing required by half. This is great for a busy lawn mowing contractor or maintenance staff looking after large areas of turf. Wetting agents are also invaluable in summer.
As soils become very dry in drought, they are often less likely to let the water penetrate when it does rain and often the whole lawn, or sometimes patches, become hydrophobic (dry patch). So at the beginning of summer, offer your clients the opportunity to have a wetting agent applied. I find Stamina G from Nuturf an excellent product, as once the water gets into the soil, it coats the soil particle.
So rather than repelling water it, attracts it. Stamina G also contains a small amount of Penetrant, which releases the soils surface tension and allows the water to penetrate. If a lower cost is needed for very large areas, then try Stamina Express which is only a Penetrant. However, it does not last as long as Stamina G
Getting water into the soil rather than running off is one of the most important things you can do for a lawn in summer. Spring aeration of the lawn, or de-thatching renovation before summer will also help the lawn cope much better with the dry summer. Compaction in particular, will make a lawn far more susceptible to dry times. If sections of lawn are really suffering in the summer, try asking the client to reduce wear on those areas.
Weeds And Pests In Turf And Gardens
In summer, two weeds can drive you nuts; Nut grass and Summer grass. Nut grass can either be dug up or sprayed out. Round Up only burns the top growth and tends to simply slow its spread down. On a recent overseas trip, I noticed people using a chemical called Sempra in their garden. They were spraying it on the Nut grass. They tried to avoid other plants, but they did say that at the correct low rate, it did not hurt the other plants, except for Sedges, which of course Nut grass is one.
Sempra is often used on lawns in this country to kill nut grass, and is registered for use on lawns. For garden use a special permit would be needed. Summer grass weeds are the other major annoying weed problem. For gardens, in particular roadside mass plantings of plants, a chemical called Fusilade will kill any grass weed and not harm plants, provided the plants are not true grasses from the Poacea family. True grasses include things such as Poa, Kangaroo grass, Wallaby grass, Festuca etc...
Grass like plants such as Dianella, Lomandras, Liriopes, Dietes, Phormium, Mondo etc, or shrubs or trees, will not be adversely affected by normal rates of Fusilade. To stop weed seeds germinating in the first place and to make your summer life easier, apply a pre-emergent to the turf or garden in early to mid spring. I find Ronstar the best one to use.
Army worm and web worm can cause major problems in Couch and Kikuyu lawns in January and February.
A Buffalo lawn can also be hit, but not quite as often. It is unusual for Empire™ turf and Nara™ Native Turf to be devastated by these bugs. Keep an eye out for these pests.
• Web Worm
The larvae feed on waste and leaf blades at the bottom of the thatch, with the debris usually being eaten first. Later they feed on the leaf, eating parts out of each leaf blade. Finally the grass stems (stolons) are the only above ground plant parts left and the turf will take on a thin browned-off appearance. You can often see a lot of grass pieces, webbing and faecal pellets
• Army Worm
In late summer, lawns all over Australia are attacked by army worm. These caterpillars are brown, greenish brown or black, sometimes with striped or triangular markings along the body. They feed on lawns in large groups, then when the food supply is exhausted, they move off together, a bit like an army on the march.
A new product from Nuturf called Gauntlet, which is a much safer product to use and more stable in sun light, is excellent at controlling these two pests in turf. It can also control black beetle in adult form. To get rid of the black beetle larvae, so they do not become adults, spray with Merit or Meridian in spring.
Mealy bug is a more rare problem in lawns, but mainly in Queensland it can effect Couch and Empire™ turf lawns. It is easy to spot, as you see a kind of creamy mildew looking residue on the lawn in Queensland in summer. Simply treat the area with Confidor. This is not a common problem. In gardens Mealy bug can be a more common summer pest problem, but again treat with Confidor.
Summer Garden Tips
Avoid summer pruning, as this is the time when plants in general can most easily be damaged by pruning. There are exceptions, so if you do prune, make sure you know the habits of the plant. As with turf, water less often, but when you do, make it a heavy deep watering. Again, wetting agents are essential. Saturaid is a good garden wetting agent. Mulch is also important, however, some mulches actually make the garden dryer. Mulches with lots of fine grade material often become hydrophobic and repel water.
So if you do mulch, only use chunky mulch with no fines. These chunky mulches can really stop a garden from drying out. Chunky mulches also stop weeds from germinating in the garden, whereas mulches with lots of fines increase weed seed germination. However, there is a place for all this fine grade mulch. It should be used as a soil conditioner. Mixed in with the soil, these organic fines not only make plants healthier, but also help the garden better survive the drought.
If plants die over these periods of severe drought and water restrictions, replace them with plants that in the eastern states need no irrigation, and in places like Perth need infrequent irrigation. Dianellas are some of the most drought tolerant plants there are. These include plants such as Little Rev™, Little Jess™, Cassa Blue®, Breeze®, and Tasred®. Lomandras like Tanika®, Nyalla®, and 'Katrinua Deluxe' are just as tough. Plants such as Liriopes, Agapanthus, and Dietes are also very drought hardy. For shrubs, try Callistemons, Kunzeas and Grevilleas.
Patio Pots And Summer Survival
The choice of both potting mix and plants will often decide whether your clients will have success or failure with their patio pot design. The best type of potting mixes for patio pots are the ones made from composted pine barks and coir. These tend to last much longer and will continue to grow plants healthily, well after the faster to break down potting mixes made from recycled organics. Recycled organics make great soil conditioners, but for patio pots they compost quicker, will often degrade within one year and suffer far more from shrinkage.
Just as important as the mix are the additives used in it. For example, both Pot Power and Shrub and Tub available from Debco, have the following important ingredients; slow release fertiliser, a wetting agent and water crystals. Slow release fertilisers are essential for good long term growth. As part of your landscape maintenance plan that you give to your clients, suggest that they ad some slow release fertiliser to their pots, preferably twice per year, and definitely at least once per year.
If patio pot plants are to live and prosper, then a six monthly, or at least yearly application of a wetting agent is essential. As the potting mix ages, it will usually become hydrophobic. No matter how much water you put into the pot, the old mix will not correctly wet up. The water will simply find the path of least resistance, usually down the side of the pot. It makes little difference if you water a hydrophobic potting mix for 2 minutes or 20 minutes, it simply will fail to adequately re-wet. Wetting agents will rectify this problem. I tend to use Saturaid, as it is in solid form and is easy to use.
Here are a few hints for clients who must take holidays and leave their beloved patio pot landscape behind for a few weeks. Firstly, of course, offer to water them for either a fee, or as a good will gesture. Another possibility is to put a big saucer under each pot. This will hold water at the bottom of the pot. This is also useful for reducing watering frequency in general. There are now some commercial products available that claim they can water your plants while away, like the milk cartons filled with gel.
Other options include putting a big bucket under the pots, or tie a tough strong garbage bag around the bottom half of the pot. Fill the pot, and hence the bucket or bag with water before leaving, and the plants will still have some water available for a longer period. Larger soft drink bottles can also be used. Fill it with water, put the lid on, and punch a small hole in the top. If you have judged it right, the water will drip out for up to a week.
When we think of summer, we think of holidays, beaches and fun times. For our plants and turf, summer can be far from fun times. There are things that can be done to better help plants survive and prosper, and in this article I have outlined lots of them.