Greenpatch Organic Seeds Open Day

If you are in the Taree area this Sunday (23rd October, 2011), Greenpatch Organic Seeds are having an open day from 10:00 am to 3:00 pm. Activities include a tour of the farm, garden and nursery; demonstrations on saving particular types of seed, and a seed-saving workshop for home gardeners so that you can learn how to save viable seed from your own backyard crops.
Members will receive a 10% discount on purchases.

For directions to Greenpatch, email: enquiries@greenpatchseeds.com.au – or phone 02 6551 4240

Camellia leaf gall

If new leaves on Camellia plants become thick and very pale green or pink, and the underside of the leaf starts becoming white – the plant is suffering from ‘Camellia leaf gall’. This is a fungal disease that affects tender new growth of Camellia sasanqua (and sometimes Camellia reticulata), especially in very humid or wet, shady conditions. Fungal diseases are a sign that growing conditions are stressing your plants and their immune system is compromised. There is no organic or chemical treatment for this disease. However, an application of seaweed extract tea will help to strengthen the cell walls of the affected plants and make them more resistant to disease.

But, first the affected growth must be removed, preferably before the undersides of leaves develop white spores. You will need a baked bean tin containing about 5 cm of methylated spirits to sterilize secateurs blades, and a large garbage bag for the prunings. Prune off all affected growth (swish the open secateurs in the spirits often while pruning) and place it directly into the garbage bag. Also collect in the bag any fallen leaves as they can harbour the fungal spores that will activate this disease again when conditions are suitable. Seal the bag and put it in the garbage if you are unable to burn the leaves. Do not compost them. Then give the soil around the plants a drink of seaweed extract at the recommended strength, and protect the soil surface with 3–5 cm of fresh mulch. Make sure your camellias are watered when the top centimetre of soil is dry, but afford watering the foliage. Also give the plants an annual application of compost or complete organic fertiliser and seaweed extract tea in late winter.

See below, how affected new growth appears, and close-up of affected leaves.


Photos courtesy of A. Lavick.

Frangipani stem rot


A New Zealand gardener is having trouble with her potted frangipani. I am posting my reply separately as other gardeners may have had a similar problem:

I live in Auckland NZ. I have white frangipani over 1.5m tall in a large pot. It last flowered about 4 years ago which was it’s first year in the pot. Now we are getting good leaf growth and new stems in the summer but the new stems rot in the winter and we have to cut them off.

There are several reasons why new growth on frangipanis can rot in winter – (1) water-logging of the mixture while the tree is dormant. (2) Lack of nutrients, such as potassium, which strengthens cell walls as well as promoting flowering. Have you given the tree any fertiliser? (3) Its position in winter is too cold for a tropical tree.

Remedies for (1) and (2): If your tree has been in the pot for 4 years, it is quite possible the roots have blocked the drainage hole/s, and that is causing the softer, new growth to rot when the tree is not using the moisture in the pot. Or, perhaps the holes have become blocked if the pot is in direct contact with the ground. Frangipanis form lots of roots and they must have good drainage.

As their roots are rather brittle, if you can’t remove the root ball from the pot easily, lie the pot on its side and hose out the potting mixture. Then carefully re-pot it into a larger pot with fresh potting mix that contains some complete fertiliser, and gently water it to settle the mix around the roots. If you can’t find a larger pot for the tree, trim the longest roots (so that they will have to grow about 5 cm to fill the pot) and re-pot in fresh mix in the same pot. Sit the pot on some pieces of tile so that the drainage holes remain clear of the soil.

Remedy for (3): Even the white frangipani (which is the hardiest) will not do well if temperatures are too low or they are in windy positions. When growing frangipanis in temperate zones, on the north side of a wall is a good position for them. A brick or concrete wall is best because the wall absorbs heat during the day and releases it slowly at night, keeping the air around the tree slightly warmer.

Disease hosts

This is a good time of year to get a head start on weeding, as no-one likes weeding in hot weather. Leather gardening gloves or rigger’s gloves are great for weeding because they provide good protection from thorns, prickly stems, sharp edges of leaf blades, and insect or spider bites.
Weeds in the vegetable garden don’t just steal water and nutrients from your crops, many are also hosts to pests and/or diseases that can spread to your vegetables. By hosting diseases, weeds undermine your work at crop rotation to keep soil healthy.
Newly germinated weeds can be removed with a shuffle hoe, left on the bed surface, and covered with mulch. They will break down to return organic matter to topsoil. Small weeds that have not formed seed heads and are disease-free can be composted or put into worm farms. Larger weeds with seed heads must be removed and destroyed by burning, or soaking in water for an extended period, or disposed of in a sealed plastic bag. Remember the adage “One year’s seeds equals seven year’s weeds” – 15 years in some cases.
For gardening advice on removing troublesome perennial grasses and bulbous weeds, see my post on perennial weeds.

Nightshade (Solanum spp.)
The nightshade weeds are members of the same family as tomatoes, potatoes, capsicum and eggplant. Nightshade weeds (and Buffalo/Noogoora Burr) are hosts to Rhizoctonia fungi that can damage potato plants and tubers; cause collar rot in many plants, and cause damping-off in seedlings. They also provide a host to verticillium wilt that can affect a wide range of vegetables, fruit trees and ornamentals. Black Nightshade is a common weed in gardens. It grows to about 120 cm high, has groups of white (or purple-tinged) star-shaped flowers with a ring of 5 bright yellow stamens in the centre, and small green berries that blacken as they mature. Birds spread this weed by eating the berries.

Cobblers pegs (Bidens pilosa)
This weed is also known in Australia as ‘farmer’s friends’ because the barbs at the end of seeds allow the masses of seeds to cling to clothing and animal fur. Each plant produces hundreds of seeds and this weed can grow into dense stands that can quickly fill an entire bed. It is a host for root knot nematodes, tomato spotted wilt, and sclerotinia rot that can affect many crop plants. Remove and destroy these weeds while they are very small.

New seed catalogue

Greenpatch Organic Seeds have released their mail order catalogue for 2001-12. They have added many new Heritage vegetable, flowering annual and herb varieties to their range. They also have 230 varieties of potted plants, tubers and bulbs that can be delivered to you in all states except Tasmania and Western Australia. As Greenpatch is in our neighbourhood, I had a lovely time last week at Greenpatch browsing through their seeds, plants and books for things to add to my collection. Like us, Greenpatch is certified-organic with the Organic Growers of Australia. All their seeds are non-GM, non-hybrid and open-pollinated, so that you can save seed of your favourite varieties from your own crop.
You can ask for a catalogue by e-mailing: enquiries@greenpatchseeds.com.au or download a catalogue from their secure website.

Rust diseases

There are hundreds of types of fungi that cause ‘rust’ on plants but each type has a limited number of host plants so that your whole garden is not likely to be overrun by rust.
Rust can occur in various seasons but it does need moisture to grow. It typically causes yellow or brown markings on upper surface of leaves, and small yellow or brown powdery growths on the underside of leaves. The powdery substance consists of fungal spores that can be blown about by wind, infecting other plants that are susceptible to that type of rust fungus.
Below, on the left, are pictures of rust on the underside if a frangipani leaf and typical signs of rust on grasses. Some leaf markings can be confused with fungal diseases. On the right are pictures of hail damage on a cycad and spores on the underside of a fern frond – which is how ferns reproduce.

Treatment
Basically, rust diseases are a sign of malnutrition that produces an unsuitable pH on the leaf surface. Plants, like humans and animals, are more prone to diseases when they have a poor diet, and rust diseases can be avoided by keeping plants growing vigorously – but this is not always possible in extreme weather conditions. Sulphur or copper are the usual treatments for rust. Both of these are nutritional elements that can be supplied by various fertilisers, including seaweed extracts. Seaweed also contains plenty of potassium that strengthens cell walls, sulphur, and trace elements (including copper) that boost plants’ immune systems.
For mild cases of rust, remove damaged parts of the affected plant and burn these, or dispose of them in a sealed plastic bag. Don’t ever compost them, as the spores may not be killed. Then give the plant a foliar feed of seaweed extract tea and water some into the ground over the root area. Improve your fertilising program using a complete organic fertiliser.
For deciduous plants, rake up and dispose of dropped leaves to avoid reinfecting the plant. Apply the seaweed tea at bud swell.
For more severe cases, after removing damaged foliage, plants can be dusted with elemental sulphur (flowers of sulphur. However, as the spores are under leaves and the dust can be difficult to apply, affected plants can be sprayed with wettable sulphur in cool weather only, as sulphur will damage plants when temperatures are over 24 degrees Celcius. Be aware too, that sulphur will also kill pest predators. If these are present on affected plants, apply chamomile tea (one tea bag to 500 ml water) instead.

Herbicide damage

Broad-leaf weed killers that contain the pyridine herbicides have caused widespread damage to many gardens in New Zealand, the UK and the US in recent years, and these herbicides are now being sold in Australia.
Pyridine herbicides include aminopyralid, clopyralid, fluroxypyr, picloram, and triclopyr. They are only effective on broad-leaf plants, but the chemicals remain active in mulch cut from sprayed pastures and in manure from animals that have grazed on sprayed pastures until the chemicals are broken down by soil microbes. Of particular concern to home gardeners and councils that recycle waste into compost for agricultural and domestic use are the products containing aminopyralid, clopyralid and picloram because they are quite persistent in compost (particularly anaerobic compost), and residue from these herbicides can damage crops for up to 24 months.

Is it just me, or do other people think it is crazy that there is widespread concern about the future of food production in Australia, and all levels of government are advising us to recycle and store carbon, yet the Australian Pesticide and Veterinary Medicines Authority (APVMA) continues to register more and more of these herbicides that damage food crops, and little if anything is being done to warn the public of the risk in using mulches, composts or manures contaminated by these herbicides.
Although there are only two pyridine herbicides containing aminopyralid (Hotshot and Grazon Extra), the APVMA has registered 59 herbicides containing clopyralid, 54 containing picloram, 27 containing fluroxypyr, and 77 containing triclorpyr, and there are several more of these herbicides awaiting approval – an impossible list to remember when purchasing mulches, manures or compost.

The problem with Australian regulating authorities is that they regard the person who sprays the herbicide as the ‘end user of the product’ and any warnings are limited to product labels without any regard for the unsuspecting gardeners who, in good faith, purchase mulch, compost or manures contaminated with the herbicide, and who may not recognise the cause of the damage to their crops because they have not personally used any herbicides.

I am very grateful to Jo T. who has sent me a link to photos of damage to vegetable plants caused by aminopyralid. These may help readers identify this herbicide problem in their gardens.
http://www.geologywales.co.uk/storms/summer-2011-aminopyralid.htm

If you are unfortunate enough to have garden beds affected by these herbicides, click here for treatment information.
See also Herbicide warning.

Further Information:
You can find Australian product names of these herbicides by going to APVMA’s Public Chemical Registration Information System page. Select herbicide and then type aminopyralid, clopyralid or picloram in the active constituent panel.
The NSW Government has been aware of the problems with these herbicides in Australia since 2005:http://www.environment.nsw.gov.au/resources/warr/SPD_ORG_ReduceRiskHerbCompost_FS.pdf
Jo has also provided a link to UK information about aminopyralid problems.

New concrete near trees

I have received an e-mail from a reader who is concerned about her neighbour’s plan to put a screen fence about 35 cm from the base of her beautiful frangipani tree, because the fence posts must be set in concrete and doesn’t know the size of the tree’s root ball or if it will damage the tree.
As new concrete near gardens is a common problem for gardeners, I am posting my answer on my blog rather than merely giving a private reply.

Generally, the feeder roots of shrubs and trees are located under the outer edge of the plant’s foliage in what is called the drip-line. Nature designed plants this way so that rain (and bird droppings, mineral dust etc.) running off the foliage falls where water and nutrients can be taken up quickly by the feeder roots (see diagram).

There are some exceptions to this rule as roots of umbrella trees, figs, crepe myrtles and liquidambers, for example, can wander all over the place in search of water. Usually, when trees or shrubs are severely pruned back, they will produce new feeder roots below the new drip-line and this can be helpful in preparing to move large shrubs and small trees.
New concrete contains lime that makes it alkaline, and hydrated lime (brickie’s lime) that is used in concrete will burn plant roots and should not be used on gardens that contain plants. If you are unable to avoid using concrete for walls or footings near established trees or shrubs, you can ask the builder to line the hole with strong plastic sheeting to prevent the new concrete coming into contact with plant roots. Plastic degrades in light but not in soil.

Adding plenty of mature compost to topsoil before planting trees and shrubs will help protect plants from the adverse effects of new concrete as one of the functions of compost is to buffer plant roots from unsuitable pH levels in surrounding soil. Where plants are established before concrete is used, adding a 5 cm layer of mature compost to the drip-line area, and covering it with 5 cm of organic mulch will help your plants. Remember to keep compost and mulch well clear of the trunk.
A more serious concern is where the concrete is to support a wall or fence close to established plants and the trees and shrubs need to be pruned on the side closest to the wall, as timing is important. Some plants, including frangipani, bleed a lot of sap if pruned when they are not dormant. The very best time for this type of pruning to reduce “bleeding” sap, is to prune during Last Quarter phase of the moon. For these plants, the wall or fence should be constructed during winter when the affected trees and shrubs are completely dormant. However, if a shrub or small tree requires a lot of sunlight or warmth for good growth, and the proposed structure will prevent this (i.e. the plant will be on the south side of the structure), it may be best to move the plant during winter for deciduous plants, or in autumn for evergreens, to a more suitable spot or into a large tub, if space is limited.
In the case of frangipanis, these lovely trees are often seen growing against north-facing walls of houses. Once concrete has seasoned, it does not seem to bother them, and they love the warmth that is stored in the wall during the day and slowly released at night.

Growing figs

This summer our area received a lot less rain than many other parts of Australia and, in March, dam levels were still low. However, a bonus of these drier than usual conditions was an excellent crop of figs. Ficus carica is a deciduous tree (usually about 6 metres high) that loves hot, dry summers as too much rain can cause the fig fruit to split, or develop fungal rot. Trees are frost tender in spring but mature trees are quite cold tolerant in winter.
The common figs (also called Adriatic figs) do not need pollination to produce fruit. Our tree is a ‘Brown Turkey’, which is one of the hardiest varieties with striped brown skin and deep pink flesh cropping from February to May. ‘Black Genoa’ has purple skin and red flesh not suitable for drying. It is a large tree cropping December to February. ‘White Cape’ has green skin and cream flesh that is excellent for jam. It is a compact tree that crops in January.
For gardeners in cooler areas of Australia, ‘White Adriatic’ (brown/green skin, pink flesh) that crops in February, and ‘White Genoa’ (green/yellow skin/ golden flesh) cropping December and February–March are recommended varieties.
Smyna figs need cross pollination with a caprifig to produce a crop and San Pedro figs only produce a small early crop without pollination.
Figs tend to be spreading trees, so choose a spot where they have room to stretch their limbs while providing you with lovely summer shade, but they respond well to a winter pruning to keep them to a manageable size. They are quite drought-tolerant when established and must have good drainage – a raised bed can assist this. They also love soil with a pH above 6.0 that contains a moderate amount of compost but don’t add a lot of other fertiliser as this can result in excess foliage growth and few fruit. If you do not have a lot of compost, an annual application 2 kg of poultry-based complete fertiliser and a drink of liquid seaweed fertiliser is usually enough. You will need to put netting over the tree as fruit begins to ripen – birds love figs.

It’s garlic sowing time

April is a good time to plant garlic in most areas. Garlic needs a soil that is rich in humus but doesn’t require a lot of nitrogen so avoid adding manures to the bed. Uncomposted manures can cause garlic bulbs to rot, although processed poultry fertiliser is quite suitable for garlic. Garlic needs a full range of plant nutrients and trace elements for healthy growth. A drink of seaweed extract tea over the whole planting area will supply a full range of trace elements. Garlic also needs a soil pH of that is close to neutral. Working a 5 cm layer of well-made aerobic compost into the topsoil will help to buffer the cloves from an unsuitable pH in surrounding soil.
We always sow garlic (and other bulbs) during Full Moon phase. That is from the 19th to the 24th of this month. Gardeners in areas with very mild winters can put the cloves (in a plastic bag) into the vege crisper of the fridge until then – because garlic likes a bit of a chill before starting to grow. As garlic needs dry conditions at harvest time, sowing in April usually allows the bulbs to mature before wet weather in late spring–summer.
Sow each clove (pointy end up) in a 5 cm deep hole, and water thoroughly. If sowing large quantities, place them 15 cm apart. Don’t forget to mulch the bed afterwards because garlic plants don’t like competing with weeds.