Rubus fruticosus spp. agg

Family: Rosaceae

Type of weed: Woody weed

Flower colour(s): White

Priority Weed State Priority Weed. (See more weeds of the State Priority Weed class.)

This is a Weed of the Month for February

Flowering Months: January, February, March, November, December

Description

A perennial, woody, semi-deciduous shrub with prickly stems (canes).

Leaves are compound (with three to five leaflets), and are dark green on top with a lighter green underside. Leaflet veins and stalks are covered with short prickles.

The five-petalled white to pink flowers are produced from November to March.

Succulent bunches of berries ripen from green to purplish black in late summer and autumn.

Note:

Yellowberry (Rubus elipticus) has already become invasive in the Lower Mountains. Wineberry (Rubus phoenicolasius) is not yet recorded as naturalised in Australia but it is noted as an aggressive garden plant. Other cultivars, including Black Satin, Chehalem, Chester Thornless, Dirksen Thornless, Loch Ness, Murrindindi, Silvan. Smoothstem and Thornfree are not listed as noxious; however, these also have the potential to become invasive.

Don’t confuse with…

Blackberry can be confused with Native Raspberry (Rubus parvifolius), particularly as it occurs in similar locations.

Dispersal

Birds and foxes play a major part in the distribution of its seed, but blackberry has some special mechanisms of vegetative growth where first year canes root down and produce another plant where their tips touch the ground.

Impact on bushland

Blackberry can sucker and it can also grow from root fragments. The fruit is eaten by birds and spread rapidly into bushland. The shrub forms dense thickets that prevent native species from growing. It also provides habitat for small birds and other animals.

Distribution

Lower Blue Mountains, Upper Blue Mountains

Alternative planting

Native plants

• Native Rubus species (R. parvifolius, R. hillii)
• Local Lilly Pillies

Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.

There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.

Control

• Crown
• Spray
• Scrape and paint

Specific control tips for this weed

Because the berries are bird spread, treat plants late spring to early summer and before they fruit, when the plant has good green growth. Alternatively, bag the fruit and place in a hot compost to kill the seeds. Other parts of the plant can be spread out to dry off the ground. Once dead, the material can be removed and composted, or allowed to decompose in place.

Blackberry is one of the more difficult plants to treat effectively, and follow up is essential for all techniques. The whole of the plant needs to be either removed or treated with herbicide; fragments of roots can reshoot, and cut canes can put down roots into even occasionally moist ground. If the technique involves removing/cutting canes, it is not necessary to take it off site if you can spread it to dry out off the ground (securely) where it will break down and can later be used as mulch. Otherwise treat it in a hot compost to break it down.

Treatment with herbicide requires attention to detail to ensure effective treatment. Timing is particularly important in cold climates. Plants must be actively growing, with lots of green leaves for a good result. Depending on the year, Spring through to late Autumn is effectiveoutside of the frost zone. Best results in the Upper Mountains have been achieved February to May.

• Small seedlings in soft ground: dig out the whole plant without breaking off roots if possible.
• Juvenile & mature plants in swamps or other soft ground: dig up the whole plant with all the roots, if done carefully by loosening the ground. This is not appropriate on slopes, riparian zones or in situations where accelerated erosion may occur.
• Mature plants with a woody crown (root ball): if the woody crown is wider than 25 mm (a 10 cent coin), the cut crown method is very effective. It involves cutting through the crown at the widest point to create maximum surface area to apply neat herbicide. Do not cut the base of the canes, as that method won’t work. Cutting the crown is a useful technique for environmentally sensitive areas as it can be done carefully by digging down to the crown.
• All other plants (seedlings, juvenile and mature without an accessible root crown): Scrape and paint the canes.
  • Scrape at least 1/3 the depth and 1/3 the length of every cane;  NB ‘length’ refers to the total length of canes before any pruning.
  • Very long canes can be pruned back to no less than 1.5m, but only if there are many leaves remaining.
  • Remove or scrape any touch downs.
• Dense thicket of blackberry with no natives: spray with a selective herbicide. Note that it is illegal to kill native plants and it can be illegal to spray in Endangered Ecological communities such as swamps.

For key points on these techniques:

• See Weed Control Techniques.
• See Risks associated with control.

State Priority Weed

Control measures:

• The plant must be eradicated from the land and be kept fully and continuously suppressed and destroyed; and the land must be kept free of the plant.
• If the weed is part of a new infestation of the weed on the land, notify the local control authority as soon as practicable.

For more info

For key points on these techniques:

• See Weed Control Techniques.
• See Risks associated with control.