Mulberries (Morus alba)

How well established is this crop?

Initial trial plantings of these crops may have been done. There is little information on plant suitability to the region and no current information on markets, commercial returns or current research. This is a new crop. Some old trees exist throughout Otago.

Background

When people talk about Mulberries they are usually referring to the Black Mulberry (Morus nigra). However other Morus species such as White Mulberry (Morus alba) and Red Mulberry (Morus rubra) are also grown for their fruit. Hybrid forms also exist between Morus alba and Morus rubra As all the trees are similar (except in size) they will be treated as one in this datasheet.

White mulberries originated in Asia and arrived in Europe centuries ago. They can grow to over 25m and come in a range of growth habits from drooping through to pyramid shapes. They were used to feed silkworms in colonial times.

Red mulberries originated on the east coast of the USA from Massachusetts down to the Gulf coast. They grow to around 20m in height.

Black mulberries are native to western Asia and have been domesticated since before Roman times. They are the smallest of the three species rarely reaching more than 10m in height. Black mulberries have a bush type shape if not trained rather than a tree shape and develop fruit at a young age.

Climate

Pollination is not required to set a crop of mulberries. The flowers are either self fertile or wind pollinated.

Winter Chilling and Frosts

The amount of chilling required to set fruit on a Mulberry depends on the variety. Some trial work on species will be required to work out which one suits your particular site.

Once again the levels of frost tolerance depend on the variety. Some trial work on species will be required to work out which one suits your particular site.

Rainfall and Irrigation

A regular water supply is recommended if natural rainfall is not sufficient during the growing season. This will ensure good sized fruit at harvest.

Wind

Although tolerant of most winds, the actual berries can be damaged if blocks are not sheltered. A good rule of thumb when designing shelter is to multiply the final height of the shelter by 10. Use that measurement as the distance you position your shelters apart. For example, when using a 6m high tree species for shelter, you will need shelters every 60m.

Make sure the shelters running east-west are deciduous. This will allow sunlight into the blocks in the winter. Position all shelters at right angles to the prevailing winds. Talk to your local nursery when deciding on the right tree type for your property. They may also be able to help with design.

Soil

Mulberries like a warm well drained soil.

Fertility

Mulberries do not need high levels of fertility to grow well. An annual dressing of a balanced NPK fertiliser will suffice. They also like a pH around 6-6.5.

Weed Control

Weed control is essential under the developing trees. Grass in the rows is usually mowed. Be very careful if you are thinking of grazing between the trees. Sheep may eat the bark from around the trees. This kills the tree by ring-barking it.

Varieties

There is a number of varieties and some research work will be required to work out which is best for your site.

Pests and Diseases

Overseas experience suggests that mulberries are generally free of pests and diseases. One expected problem on trees in New Zealand, would be bird predation as the crop ripens.

Layout

Layout depends on which species is being planted. Black mulberries are usually planted around 4-6m apart. The other species grow larger and will need more space.

General Management

Because mulberries require pruning, harvesting etc. they are best planted on a flat or gently sloping site. In Otago conditions a slightly north facing slope would be ideal to maximise the amount of heat the trees receive. After planting the trees will need regular irrigation if natural rainfall is not sufficient to keep the plant actively growing.

Shaping and pruning of the tree is best done in winter when it is dormant. Removing all dead or over-crowded wood will maintain tree vigour and health. A light summer prune will help set fruit the following season.

Harvest

Fruit from red and white mulberries is ready for harvest in late spring. They can be picked by hand or a sheet laid on the ground and the fruit shaken onto it.

Black mulberries are ready for harvest in late summer. This requires the fruit to be manually plucked from the tree. This generally means the fruit collapses and the hand of the picker gets stained in berry juice.

Equipment

Because of the area taken up with a mulberry orchard, most growers have a tractor for weed-spraying and cutting the grass. As the trees do not seem to need any form of insecticide or fungicide, this is enough machinery. Pruners and loppers are needed when shaping trees.

A single or a few trees in the garden can be managed even more easily.

Returns

Because this is a very new industry it is hard to give good financial information. Further processing into various products seems to be the best way to maximise returns from mulberries. These products include pies, cakes, sauces, wines and dried fruits.

Contacts

Contact your local branch of the New Zealand Tree Crops Association for the address of growers in your area. www.treecrops.org.nz