How to Grow Lawtonberries in Australia

Lawtonberry is 'Lawton', an old American blackberry in the rose family, Rosaceae, usually listed as Rubus philadelphicus. It is grown for its purple-black berries on upright, thorny canes. Planted as a bare-root cane in winter and trained on a trellis, it crops each summer on canes that grew the year before. A common mistake is cutting out those new canes, and with them the next crop.

Three mistakes that matter

1. Cutting the new canes. Lawtonberry fruits on canes that grew the previous season, so a hard winter prune of the green new canes removes next summer's berries. Cut out the canes that have fruited and keep the strongest five or six new ones, as Pruning and Training explains.
2. Letting it wander. Lawton suckers strongly, cane tips that touch the soil take root, and birds carry the seed away. Pull suckers while they are small, keep every cane tied up on the trellis and net the ripening fruit.
3. Dry soil and hot afternoons at fruiting. Brambles that dry out while flowering or fruiting give a poor harvest, and harsh sun can scald ripening berries. Mulch deeply, water steadily and give the row afternoon shade in hot districts.

When to plant

Plant dormant bare-root canes in winter, before the buds burst: from about June in milder districts to September in cold ones. Blackberries crop best after a cold winter, so the cooler zones suit them most and the tropics do not suit them at all. One planting keeps cropping for many years in good soil, so there is nothing to plant in succession.

Frost does not harm dormant canes, so in cold districts plant as soon as the soil can be worked. Snow that falls after bud burst can break canes, which is one more reason to plant early and tie in promptly.

Site, soil and setup

Avoid a spot where brambles, roses or stone fruit grew recently. Crown gall bacteria (Agrobacterium tumefaciens) attack many plants in the rose family, and an infected plant cannot be cured.

Blackberry and the weed laws

Wild European blackberry (Rubus fruticosus aggregate) is a Weed of National Significance, declared in every state and territory. Government sources place North American blackberries such as Lawton outside that group, but each state words its law differently.

Wherever you garden, the law expects you to stop a plant you keep from spreading. Follow the second of Three mistakes, and bag prunings instead of dumping them.

Planting Canes

Lawtonberry starts from a dormant bare-root cane, a short stem on a root system, planted straight into the bed beside its trellis. Due to quarantine restrictions and our shipping policy, we cannot send Lawtonberry canes to Western Australia or Tasmania.

Bare-root preparation

Unwrap the cane as soon as it arrives and check that the roots are still moist. Plant within a few days, keeping the roots in their damp packing until then. Shake the packing off before planting and keep it out of the hole, since it holds water but feeds nothing. Soak the roots in a bucket of water while you dig, and trim off any broken roots.

Planting the cane

• Dig a hole twice the width of the roots and 10 to 15 cm deep, 1.5 to 1.8 m from the next plant.
• Spread the roots out and set the plant at the depth it grew in the nursery, shown by the soil mark on the stem.
• Backfill, firm gently and water in with seaweed solution at 30 mL per 9 L.
• Cut the cane back to about two buds so the plant puts its energy into strong new canes from the base.
• Mulch with compost or straw, keeping it clear of the stem.

Setting up the trellis

Lawton's upright canes reach 1.5 to 2 m, and the fruiting canes still need tying in. Set sturdy posts about 2 m tall and up to 3 m apart. Stretch four or five wires between them, 30 cm apart, with the lowest 45 cm above the ground.

Care by growth stage

Steady water from flowering to the last pick, and a light hand with nitrogen late in the season, decide the crop. Stages follow the seasons and shift a few weeks between zones. The table repeats every year, although a newly planted cane carries little fruit in its first summer.

Stop feeding once picking ends: late nitrogen keeps canes soft into winter and softens the fruit. Before the berries colour, cover the trellis with white, wildlife-safe netting on a frame, taut, with mesh too small for a finger. Net early, because birds that find the crop hunt for gaps.

Pruning and Training

Each plant carries two sets of canes at once. A cane in its first year (a primocane) only grows. In its second year (as a floricane) it flowers, fruits and dies, so prune to keep the two sets apart.

Wear thorn-proof leather gloves and long sleeves for every pruning job, as staying safe in the garden describes. Top-dress the row with compost after pruning and put the straw mulch back.

Companion planting

A Lawtonberry row is best kept to itself, with low flowers along its edges for pollinators and pest predators.

Grows well with

• Alyssum, whose small flowers draw hoverflies, whose young prey on mites and other small pests.
• Cornflower, sown along the path side, which gives predatory insects nectar, pollen and shelter.

Keep apart

• Raspberry, blackberry, boysenberry, loganberry, youngberry, tayberry and silvanberry, each on its own trellis, since brambles share grey mould, rusts and viruses.
• Wild blackberry thickets, which harbour blackberry leaf rust (Phragmidium violaceum) and other bramble troubles.
• Vegetable beds, which the suckers invade from the row.

Harvesting Fruit

Pick when berries have turned fully purple-black and feel slightly soft; left to ripen fully on the cane, they develop the best flavour.

• Expect the first real crop in the second summer, once the canes that grow after planting have had a year.
• Pick every 3 to 4 days through the season, which in the Dandenongs east of Melbourne runs from about December to February.
• Pick when the fruit is dry, because wet berries rot faster.
• Roll each berry off with a gentle pull: a blackberry keeps its core, unlike a raspberry.
• Lay berries one or two deep in shallow containers so they do not crush.
• Bin mouldy fruit as you go, and freeze stung fruit sealed in a bag for two days before binning it.

Chill unwashed berries, covered, and eat them within a day or two; Lawton keeps better than most blackberries. Wash them just before use, and freeze them for longer keeping.

Eat them fresh from the cane, or bake them into pies and simmer them into sauces and the jam they are best known for.

Common problems

Canes browning and dying after harvest. This is normal: a cane dies once it has fruited, so cut it out as Pruning and Training describes.

Pink, cooked-looking drupelets. This is sunscald, which often strikes when strong sun follows cool, cloudy weather; see Three mistakes.

Crumbly berries that fall apart. Poor drupelet set can signal raspberry bushy dwarf virus, which bees spread in pollen. It cannot be cured, so replace badly affected plants with clean stock.

Berries that stay partly red. Where part of a berry stays hard and red while the rest ripens black, the red drupelets never ripen. This is redberry mite (Acalitus essigi), a minute mite found in Victorian and Tasmanian blackberries, worst within about 30 m of wild blackberry.

Berries eaten before you pick them. Birds can strip a blackberry crop, so net the trellis before the fruit colours, as Care by growth stage describes. Read more

Pests and diseases

Most bramble troubles in Australian gardens start in wet, crowded canes or in hot, dry weather.

Two-spotted mite (Tetranychus urticae). These minute mites feed under the leaves in warm weather, leaving pale speckles that turn to a silvery sheen. Sprays kill the predatory mites that control them, so hose leaf undersides in dry spells. Read more

Grey mould (Botrytis cinerea). The most serious berry disease in Australia shows as short grey fur on drupelets, after infection at flowering in cool, wet weather. Keep new canes apart from fruiting canes for airflow, and pick often.

Cane anthracnose (Elsinoe veneta). Round purple spots appear on new canes in late spring and turn grey in the middle. Cut out badly spotted canes. Where it returns, spray dormant canes in winter with a copper fungicide whose label lists the disease on blackberry, at the label rate.

Blackberry leaf rust (Phragmidium violaceum). Released in Australia to weaken wild blackberry, this rust makes red-purple leaf spots above yellow pustules that turn black. Erect blackberries are less susceptible, so pick off affected leaves and keep the canes thinned for airflow.

Queensland fruit fly (Bactrocera tryoni). A native pest throughout eastern Australia, it lists blackberry among its host fruits. Females lay eggs in ripening fruit, so pick promptly and do not let fallen fruit lie under the plants. Where it is active, use fine insect mesh in place of the bird net after flowering, secured to the ground and clear of the fruit. Read more

Prevention first

• Start with clean canes from a reputable supplier, since viruses and crown gall arrive on infected stock.
• Prune as Pruning and Training describes, so air moves freely between the new and fruiting canes.
• Water the soil, not the canes, and keep the base of the row free of weeds.
• Clear any wild blackberry on your land near the row, since it carries the most redberry mite.

Tips

1. Not sure which canes have fruited? Bend them: old canes are brittle and snap, while new ones flex.
2. Freeze berries in a single layer on a tray before bagging them, so they stay loose and can be tipped out by the handful.
3. To stretch the picking season, give an earlier bramble such as boysenberry or youngberry its own trellis nearby: Lawton ripens after them in the south-east.