Planting Guide and Garden Care
A guide for planting and garden care in the cooler climate of the Southern Highlands.
It is amazing how a few warm days can trigger an explosion of weeds that are running to seed very quickly. So remember the old saying that one year’s seeding is seven years weeding.
Digging weeds can be very effective but time consuming depending on the size of your garden. If you are fussy about your lawn selective weed killer can be used to remove the weeds. Remember that those containing Dicamba have been shown to adversely affect shrubs and trees. I spray my lawn for one metre from garden edges which reduces weeds in the garden beds.
There are several brands of Glysophate, the most common being Roundup and Zero. Glysophate is absorbed only by the green parts of a plant and is most effective when the weeds are growing vigorously. Always follow mixing instructions with all chemicals. If you use too much there is the possibility you will burn the top growth quickly and so the herbicide will not be transferred to the roots. With some tuberous types of weeds you can get regrowth. Be very careful that you do not allow Roundup to drift onto non target plants.
Bulbous weeds will require repeat spraying, so every time leaves appear you treat them like the enemy. In time the bulbs will succumb.
Woody weeds are best treated by slashing and spraying immediately, while tree stumps should be painted with undiluted Glysophate onto the freshly cut surface within 30 seconds.
Glysophate is broken down quickly by the colloidal content of most soils but be careful in sandy soils as some damage has been known to occur to surrounding plants, particularly roses.
You should use a designated sprayer for herbicides only and mark it very clearly.
Now, looking on the bright side, it is rose time. In November and December you reap the rewards of nurturing your roses. Depending upon the types you grow they can give pleasure until late autumn.
Roses should be well mulched and fed every 6 to 8 weeks. Avoid wetting the foliage when watering as this encourages black spot and mildew. Check for aphids on the sappy new growth. Spray once with a systemic insecticide such as Confidor or more frequently with pyrethrum or similar. A recommended spray, which is cheap and environmentally friendly, is 3 teaspoons bi-carbonate of soda with 3 teaspoons white oil mixed in 4 litres of water.
Bowral Co-op has good mulching hay for $10 per bale, which is very cost effective compared to other mulches.
At our last meeting a question was asked about the use of Confidor tablets. They are expensive to use, harmful to earth worms and also there is the likelihood of lace bug and red spider mites building up immunity over a period of time. Instead of being zapped once with a spray there is a slow release through the plant. During dry periods it would be difficult to gauge the effectiveness of the tablets.
- Remove the dead flower heads from bulbs and let the foliage die down naturally. Don’t be tempted to tie the foliage in knots for tidiness.
- Prune spring flowering trees and shrubs immediately after flowering if needed.
- Spray azaleas and rhododendrons with Confidor the first week in November to protect them from red spider mite and lace bug. Timing is crucial as the Confidor will kill the mites as they hatch. A follow up spray is needed the first week in January.
- When planting out tomato plants bury them up to the first set of leaves. They will send out roots up the buried stem and grow into a much sturdier plant. Feed with Blood & bone with potash when they flower.
Highland gardens have undergone a wonderful transformation in the past few weeks. It looks as though a magic wand has been waved over our gardens and suddenly they have emerged from hibernation.
While the weather plays a part in this other factors make a huge contribution. Gardeners often forget that soil is the most important element in gardening. It is the basic raw material of the gardener’s art.
Soils with an abundance of fungi, bacteria, nematodes, worms, beetles and so forth have the ability to provide plants with all the nourishment they require, and do so in a healthier manner than using synthetic nutrients.
Rather than thinking that soil is a “bank balance” of plant food it should be considered as a living organism which is respiring and full of life, which it is. Soil organisms give healthy structure to soil and make nutrients available to plant roots. Gardeners should assist these invisible ‘beneficials’ by keeping a mulch of organic matter on the surface and avoiding unnecessary cultivation.
Not digging soil will lead to a more healthy soil population as you are not disturbing the soil’s food chain. Plants will be more vigorous and require less chemicals to keep disease at bay.
The soil’s food chain has invisible bacteria at the bottom and frogs, mice, and birds at the top with mankind’s foot-print over all the inhabitants underneath.
There’s an incredible dynamism and inter-linkage to the working part of our soil. Impairment of any one group of organisms has bad effects on the others.
1. Bacteria are vital to the planet’s health. Most help to decompose organic matter. When bacteria die, the nutrients they recycle become available to plants.
2. Fungi can travel by increasing in length helping aerate soil and move nutrients around. Plant root use mycorrhizal fungi to fetch and unlock minerals, especially phosphorus.
3. Protozoa include amoebae, ciliates and flagellates, which work with and mostly live off bacteria. Protozoa may supply as much as three quarters of plants’ nitrogen requirements.
4. Nematodes or roundworms, are prolific and mostly beneficial, consuming everything below them in the food chain, and some above e.g. slugs. Nematodes help to mineralize nitrogen.
5. Arthropods include mites, spiders, beetles, springtails (soil fleas) and millipedes, whose main role is to shred organic matter such as leaves, speeding their composition.
6. Earthworms make casts up to 50% higher in organic matter than surrounding soil. Their digestive enzymes make nutrients more available to plants. They can open up compacted soils and increase soils’ water-holding capacity.
7. Gastropods are slugs and snails, who play a vital role despite at times devastating plants. Most gastropods live below the surface and convert organic waste to a more decomposed form. Their excretions help bind the soil particles together.
Now is the time to mulch to keep the soil damp and suppress weeds and provide food for the “beneficials”. Mushroom and garden compost will most benefit the structure of your soil. They break down much faster than wood chip mulch, but are better for plant growth. Lucerne hay is excellent, but check the price before you buy. Lawn clippings should be composted before using on the garden as they can form an impenetrable barrier and water will run off rather than soak through to the soil.
Dead head spring flowering bulbs as the flowers die off unless you want them to seed.
Spray roses with Confidor if aphids are a problem. This is a systemic spray which will last in the plant for 5 weeks.
Tidy clumps of bearded iris and feed with Osmocote or Multigrow and water this in.
Camellias can be pruned after flowering to reduce the height or open up the bush. Remember that small birds should be able to fly through the bush, according to Jim Powell. Sasanqua hedges can be trimmed then fertilize and mulch.
Our Tour Director organised a very interesting visit to Paradise Plants last month. Bob Cherry has sold the nursery but continues to hybridise some plants. Bob established his reputation collecting and growing camellias and is introducing a new camellia next year. It is a cross between Camellia pissardii sp. pissardii and C. Japonica. It is a very compact plant suitable for tubs and small gardens with buds in every leaf node. We saw the plants which are in different shades of pink, some informal double and formal double. I thought the plants were very impressive.
Bob has been hybridising polyanthus and we were privileged to be taken to the “poly” tunnel where thousands of pots were being cleaned and pollinated. As well as growing plants he also has a market for polyanthus seed. Paradise polyanthus are available through Bunnings and at Anchors Fruit Market in Bowral. Price at Anchors is $2.99 per pot.
Our Editor included an article about azaleas in last month’s Bulletin. They have become unpopular because of the belief they need a lot of water, and problems with lace-bug and petal blight.
I have been collecting azaleas for the past forty years and with selection of suitable species for our climate and planned spraying only twice a year I have no problems. Once established azaleas do not need much additional watering. They do need to be sprayed the first week in November and the first week in January for lace-bug. By spraying at these precise times you kill the emerging insects.
There are several groups of azaleas. In Australia the two most popular types are the Belgian Indian hybrids which are mistakenly called Indicas. The Belgian Indian plants require warmth and humidity and in this area are difficult to grow, and it is this group that suffer from petal blight.
The group of large growing, single flowered plants, usually labeled Azalea indica, such as Alba Magna, Alphonse Anderson, Exquisite, Splendens, Violacea grow well in this district.
It is the Kurume azaleas, originating in Japan that thrive here. They provide an absolute explosion of spring colour. The Kurumes are a small flowering variety and cover themselves in bloom.
The deciduous azaleas flower in October, and come in the brilliant yellow and orange colours that are not seen in rhododendrons or other azaleas.
The most garden worth plants I could recommend are of the Erica family and their cousins the callunas, commonly called heaths. Both groups are very attractive to bees particularly during winter when there is very little in flower. Erica carnea and x darleyensis grow very well in cold climates and have no insect or disease problems. Some of the plants originating in South Africa can be frost tender in this area. However it is these plants that are the most spectacular colourwise. Ericas and callunas are long flowering and I find them very compatible plants to grow with conifers and other fine foliaged plants.
The westerly winds have been blowing as they should throughout August so please check any trees that you have staked to make sure you are not strangling them. The plant tie should not be wrapped around the trunk, but in a figure of eight around the main stem and the stake.
- Plant citrus remembering 3 rules – sunlight, good drainage and fertiliser. Citrus are heavy feeders and need fertilising every 2 or 3 months with a complete fertiliser.
- Prune hydrangeas back to the 2nd or 3rd pair of buds, and cut out weak growth. If the stem has not flowered previously (it will have a green bud at the tip) don’t cut it back as it will be the first to produce flowers in December. Feed with Organic Life and use a good organic mulch.
- Divide and replant hellebores.
- Fertilize camellias with Organic Life.
Now you can sharpen your secateurs and prune your roses towards the end of the month. If you are nervous about pruning I suggest you attend the rose pruning workshop being conducted by our rose expert, Sue Kingsford. Details are under workshops. The general principle for bush and standard roses is to remove old unproductive wood back to the graft and then shorten other stems by half, always cutting at an outwards facing bud. Spray after pruning with lime sulphur or Kocide to prevent fungal diseases.
I regard this month as the time to tidy and weed so that you are prepared for Spring and can then keep your garden relatively weed free. It is important to weed your clumps of bulbs before they flower so that you do not damage the emerging flowers. Fertilize bulbs when the new growth appears with blood and bone with potash.
At a recent meeting a question was asked about a mature evergreen Alder being a risk to a septic system. And indeed it is! The roots are extremely invasive wherever there is moisture. About twenty years ago they were very fashionable because of their rapid growth and supposedly being evergreen. Actually they lose their leaves in late July for about six weeks. As the Alders mature nothing will grow beneath them because of their dense root system. They do make good paddock trees. If you need to buy bare-rooted trees or roses do so now as the sap will start to rise as warmer weather approaches and the plants will start to send out new roots. Bare-rooted trees will need initial staking with three stakes. Hessian binding is the best to use to tie big trees but the cotton tie is quite good for smaller plants. It does stretch and tends to rot faster.
- Sow broad beans; cabbage; herbs; lettuce; onions; peas; silverbeet; spinach.
- Cauliflowers should have the leaves tied over the head to keep the curds white.
- Transplant asparagus crowns; potatoes & rhubarb crowns.
- Cut back dead tips of evergreen ornamental grasses, but cut to the ground those that die off completely. Tidy up dead leaves etc. by raking the grasses with a small hand fork.
- Cut back strawberries aggressively and fertilise with a mix of 5 parts blood & bone to 1 part potash. If your plants are getting old it is a good idea to start with new runners from the outside of the clumps. If the fruit has been getting smaller this is a good indication.
- Fertilise stone fruit 5 to 6 weeks before flowering and clear any grass and weeds from around the trunks.
- Fertilise paeonies with azalea food which is low in nitrogen so that there is not excessive leaf growth at the expense of flowers.
- Prune crepe myrtles now if they were not trimmed after flowering. They flower on new wood so if pruning is left any later it will be detrimental to next seasons flowers. Trimming encourages better flowering.
- Winter flowering ericas and heathers are still putting on a good show of blooms but trim them as soon as they finish flowering to keep them bushy and compact.
- Divide overcrowded waterlilies and replant in aged cow manure into which a few granules of Osmocote Plus has been mixed. Fertiliser tablets suitable for pond plants are available from Bowral Pets & Aquarium in Station Street.
not already done, give them a dressing of manure or other organic type fertiliser, to help the new growth to be sturdy, and don‘t let the root zone dry out.
As is often the case, particularly in the Highlands, Spring this year is a contrast of changing weather, alternately warm and dry, then cool and wet again, although the worst of the frosts should be over now. There is more than enough to do in the garden to keep us very busy.
Spring flowering bulbs are finishing, but this is the time the bulbs are utilising nutrients to prepare for next year’s flowering, so don’t let them dry out and don’t cut or tie up the foliage – you can even give them a light feed if you are fertilising nearby parts of the garden. If foliage persists 8 weeks after flowers have finished, you can cut it back then – it will be untidy by then anyway and will have done its work. If you want to move daffodils, dig them up as the foliage finishes, but plant them again in the new position straight away, marking the place with a small stake. If you have the energy to dig up tulips, do it in early to mid November. I leave the bulbs in the ground and find that given enough water when growth starts next Spring, they repeat flower quite well, and even multiply.
The Tulip time Corbett Gardens Dig up Day is scheduled for 8.00 am to 11.00 am on 12 November and is an opportunity to acquire some very good bulbs very cheaply. When you take your bag/s of bulbs home, wash off the mud and soil and spread them out in a sunny place to dry for a few days. Then dust them with a fungicide powder such as Bayleton and store them in small quantities in cotton or paper bags (not plastic) in a cool dark place. Check the bulbs periodically through the Summer for mould and if needed, dust them again, discarding any that go soft.
Camellias can be pruned after flowering: Jim Powell’s advice when he spoke at the September meeting was that the traditional Japanese approach is to thin out the centre of the bush so that “a small bird could fly between the branches”. It takes a fair bit of courage to attack a big old Camellia in this way, but they are remarkably hardy plants, and you will be surprised at the regeneration. Feed, water and mulch them before the weather gets too much warmer, as for other Spring flowering shrubs such as Pieris.
Since the whole garden is in the midst of its Spring growth spurt now, everything benefits from feeding – compost and cow manure for the acid lovers such as Camellias and Azaleas, complete dry food for iris, complete rose food regularly for roses, and high Potash fertiliser for fruiting crops. If we experience another dry spell, keep the soil damp as well.
Tomatoes can be planted out now – the leggy seedlings such as Grosse Lisse can be planted quite a lot more deeply than in the punnet or seed tray – they will make roots from the buried stems. Don’t plant them in the same spot as last year though – the plants will be healthier if you plant them in a spot that took root crops or leaf crops last season. The tall varieties need a sturdy stake at planting time. If you plant out pumpkins, zucchinis, cucumbers and squash now, and a cold spell is forecast, it pays to cover the little plants at night, either with some thick lucerne or pea mulch, or empty feed bags to help to protect them. Uncover in the morning.
You can make very good liquid feed for the vegetable garden by putting the equivalent of a small bag of any sort of manure in the bottom of a large bin such as a wheelie bin or 44 gallon drum. Fill with water, cover and allow to steep for about a fortnight. Dilute the resulting liquid with water, to the colour of weak tea and use especially on any leaf crops – the high Nitrogen content produces strong growth and encourages worm activities.
In the vegetable garden prepare the beds for tomatoes and cucurbits and protect other seedlings from snails. You can start seeds of all the summer vegetables, if you have a warm sunny spot, and seeds started now should be strong and sturdy seedlings to plant out at the end of October.
Although the calendar labels August as the last month of Winter, if there are daffodils, jonquils, Hellebores and Camellias flowering, in the words of the old song, it might as well be Spring. It has been such a cold, wet, windy Winter though, it‟s been hard to find days fine enough to spend useful time in the garden, consequently many gardens are in dire need of a Spring clean up. Running the mower over the grass works wonders, even if only to tidy the winter lawn weeds like nut grass and winter grass. A dressing of sulphate of ammonia will give the lawn a lift and help to suppress weeds as growth resumes, but couch and buffalo will still be looking bleached by the cold, and it is better to leave them another month or so before fertilising.
Roses should be pruned now, if not already done. You may find that some varieties have already started putting on new growth, a sure indicator of the need to tidy them up, otherwise the new growth will start at the ends of long gangly stems and will never be strong and sturdy. Cut out dead and shrivelled growth right back to the base, and any thin, yellow, or twiggy stems, back to the main stem, then shorten the remaining strong stems back to the size you want the bush. Just aim for 3 -5 good strong stems, with an open centre to the plant, then give them a dressing of complete rose food, about a good handful to the square metre. Cow manure is wonderful for roses too, and Lucerne mulch feeds the soil as it decomposes.
Control snails around emerging and flowering bulbs, and feed the bulbs with bulb food or complete fertiliser, as the flowers finish, to ensure good strong bulbs and therefore lots of flowers, for next year. Dead head daffodils as the flowers finish, otherwise they spoil the look of the clump or row.
It is a good idea (when we get a few dry days) to spray peaches and nectarines with fungicide just as flower buds are showing colour, and again when petals fall, to control leaf curl disease. The same treatment for plums will help to control brown rot.
This is the last month for planting bare rooted trees – as always, give them a generous sized planting hole, and you may want to try Angus Stewart‟s suggestion of planting them somewhat more deeply than in the traditional planting method. The suggested benefits of deeper planting are that the plant is more stable in the soil, it does not dry out as readily, and some species will actually form a larger and healthier root ball, by forming roots up the buried section of stem. I would not try it with species that are fussy about perfect drainage, for example Daphne, because the deeper the planting hole, the more likely you are to be digging close to, or into the subsoil, which is much wetter than the topsoil. Roses though, are usually planted with the graft several centimetres above the soil surface whereas in fact they are much less prone to breaking at the bud union, if planted with the graft right down at soil level, and they are also less inclined to sucker if planted fairly deeply.
In the vegetable garden you can really get started and put in beetroot, broad beans, cabbage, carrots, corn, lettuce, parsnips, peas, and spinach. If you have a green house you might want to try some early sowings of tomato and pumpkin seeds, but they can‟t be planted out until frosts are well and truly over. Plant pumpkin seeds in small individual pots so that you can plant them out without disturbing the little roots, and they will establish much faster.