Mulberries are gaining attention these days in permaculture circles around the world. They’re easy to grow, prolific, and new hardy varieties mean that they can be grown anywhere between zone 4 and 9. Minimal maintenance and large crops make them a great choice for a backyard orchard.
Growing up in southern California (zone 9), fruitless mulberries were one of the very best shade trees. Drought tolerant, they’d grow in the desert where few other trees besides palms could thrive. When our horses stripped the bark from one of our younger trees, it came back from the rootstock as a fruit-bearing mulberry and I had the chance to try my very first one. That resilient, drought-tolerant rootstock produced truly spectacular fruits.
Now I find myself on the other side of the country, living in zone 4 Vermont, and plant breeders have recently developed a number of cold hardy mulberry trees. I’m excited once again to be able to pick these rich fruits right off the tree.
Mulberries are small blackberry-like fruits that grow on small to medium-sized trees. While the fruits are somewhat similar to blackberries when ripe, they’re actually not related at all. The small unripe fruits look like some sort of alien lifeform just after pollination, and they don’t really look like berries at all until they’re fully ripe.
Mulberry trees can be grown from cuttings, grafted or planted from seed. Like many other tree species, including apples, they don’t come true to seed and seedlings will be somewhat different than their parent. Softwood cuttings during the growing season are the most reliable propagation method (here’s how).
Regardless of how the mulberry tree gets started, care is pretty straightforward. Mulberry trees prefer well-drained, fertile soil and they’re generally drought tolerant. For the most part, they’re adaptable trees, but they cannot withstand wet soils. In the first year of growth, the trees require 1 inch of rain per week and will need to be watered if the weather is persistently dry. Once they’re established they shouldn’t require watering except in the dryest climates.
Plant mulberry trees roughly 25 feet apart. For the first few years, they’ll grow rapidly. Once they reach a height of 25-30 feet tall, growth slows down dramatically but be sure to allow space for that initial growth spurt. Newly planted trees begin bearing fruit in as little as 2-3 years.
Like blackberries and blueberries, mulberry fruits stain, and it’s best to plant them far from common walking areas. Even if you’re diligent with picking, there’s still likely to be a substantial windfall crop, and many people harvest by laying out sheets below the trees.
An old-time permaculture book called Tree Crops: A Permanent Agriculture recommends planting them so that they overhang chicken yards or pig pens. It claims that a single mature tree can produce enough fruit to feed several pigs for at least a month with no supplemental feed during the fruiting period. That doesn’t sound like rounded forage, but it’s still a great way to supplement and dramatically reduce your feed costs. Rather than thinking about dropped fruit as an inconvenience, think about where a mulberry tree can be planted to add value with any fallen fruit.
Mulberries generally ripen in early summer, with harvests spread out over a full month. Once a tree is mature it can produce between 60 and 100 gallons of fruit, much of which will be harvested by birds. Still, even excusing large losses to support bird populations, it’s possible to harvest way more than a family can eat from a single tree. In the first few years of growth, crops will obviously be smaller.
Since mulberries are preferred by birds, some farmers actually grow them as decoy crops to protect more valuable market crops. If a scarecrow and bird netting won’t keep birds off your summer fruit, try a mulberry tree instead. Even if you never harvest the mulberries, it’ll improve your harvest of other things around the same time like pie cherries and summer raspberries.
Cold Hardy Mulberries for Zone 4
For many years, just about every variety of mulberry was considered hardy to zone 5 or 6. Relatively recent plant breeding has developed several cold-hardy varieties that seem to grow and fruit well in zone 4. If you’re in a warmer zone, there are dozens of varieties to choose from.
Depending on the variety, mulberries are either self-pollinating or require separate male and female trees to produce fruit. Be sure to check on the exact variety and make sure you get a male if necessary. Up here in the north country (zone 4), all the cold-hardy mulberry varieties I know of are self-fruitful.
- Illinois Everbearing Mulberry – The most commonly available variety of hardy mulberry. Fruit ripen slowly over a long period, sometimes as long as 3 months. Heavy crops of sweet fruit annually and hardy to -25 F.
- Northrop Mulberry – Sweet fruited and hardy.
- Viola’s Lavender Mulberry – The product of a chance seedling in Southern Indiana. Has a light lavender colored fruit that is supposedly less staining than darker colored varieties. One of the earliest ripening cultivars. Self Fertile and hardy to zone 4.
- Collier Mulberry – An early fruiting hardy mulberry variety.
- Kokuso Mulberry – A Korean variety with wonderful fruit flavor. Fruits ripen early and over a relatively long season.
- Gerardi Mulberry – A natural dwarf, trees say under 6′ tall making them perfect for the backyard grower. Ripens over a period of 4-5 weeks. Space trees 6 to 10 feet apart. Self Fertile.
- David Smith Everbearing Mulberry – Trees originate in Oxnard, NY and are hardy to zone 4, producing heavy crops of berries. Said to be more compact than many varieties.
There are three more varieties I can find that are supposedly hardy to zone 4, but there’s little specific information about each cultivar. Those include Russian #1, Lawson Dawson Mulberry, St. James Mulberry and Oscar’s Mulberry.