I’m currently enjoying the fruit from the mulberry tree in my backyard and thought you might want to try growing this tree as well. Mine produces dark purple fruit that is a sweet, juicy and a healthy treat. The tree grows fast, is easy to maintain and has been virtually problem-free.
About 12 botanically separate species of mulberries are all in the morus (mulberry) genus in the much larger Moraceae family. The family also includes breadfruit and many members of the ficus or fig genus.
Mulberry trees were likely brought to Hawaii by Don Francisco de Paula Marin in the early 1800s. The cultivar “nigrobacca” is from the original Morus alba (white mulberry). It is the one usually grown here for its tasty dark fruit. This attractive tree also provides shade and is somewhat drought tolerant.
Morus alba is native to China where it was cultivated for thousands of years as food for silkworms. The worms produce cocoons that are made up of a silky thread that is processed into silk fabric. Today, mulberry trees are grown throughout the world to feed silkworms resulting in over 70 million pounds of silk produced annually.
Beyond silk production, mulberry trees have many attractive features. Their large, oval, dark green leaves that grow on spreading branches emanating from a distinctly furrowed bark on the tree’s trunk all add to its appeal.
Mulberry trees are hardy and adaptable. They prefer a full sun location but will tolerate a variety of conditions at both lower and upper elevations. In ideal conditions, the trees can grow to over 40 feet over time but their rounded crown can be maintained lower with judicious pruning. Once established, they can thrive with limited water.
Male and female mulberry flowers appear on slender inconspicuous spikes or catkins that grow at the axils of the current season’s growth or on spurs of last years growth. They are pollinated by wind-born pollen that the male flowers fire into the air by releasing stored energy in their stamens.
The resulting fruit is actually an aggregate of berries, each with its own seed, that forms a cylindrical hanging cluster. The fruit is white or green when it first appears and turns red then dark purple as it ripens. The berries on a branch will not a ripen at once but will do so over an extended period.
We are not the only beings that enjoy mulberries. If you want to beat the birds to the fruit, you need to pick daily or cover the tree with bird-proof netting to protect the berries. Since mulberry juice can stain, you might want wear gloves and aprons when picking or handling to avoid purple stains on your hands or clothing. The juice can also stain sidewalks and driveways, so plant your mulberry tree away from structures or light-colored paving.
The berries will keep for several days in the refrigerator or can be frozen or dried for later use. They are fun to eat out of hand right off the tree or can be used in pies, muffins, tarts or sauces. They also make good wine.
The mature plant, especially the bark, contains resveratrol which is known for cancer prevention and to promote longevity. Parts of the plant are often marketed as nutritional supplements with a variety of health benefits. The white sap in the unripe fruit and green parts of the plant is said to be intoxicating and mildly hallucinogenic, but can also give you a mean headache.
Propagating mulberries can be done from seeds or cuttings. Most often the trees are reproduced from cuttings to shorten the time to fruiting. Choosing a semi hardwood branch about the diameter of a pencil and four to six inches long with several buds, should work. Dip the cut end in a rooting hormone and place it in a medium made up of equal parts of vermiculite and perlite. Keep the rooting medium moist (not wet) and roots should develop within thirty days.
Plant out when the cuttings are producing new leaves and roots have fully developed. Choose a sunny location with loose soil with good drainage for best results. Mulch around the tree and keep the soil a bit moist until the tree becomes established. At that point, you may only need to water deeply once a week and even less when it rains.
Maintaining a mulberry tree requires light fertilizing twice a year and occasional pruning to maintain a desired size and shape. Avoid heavy pruning, however, to prevent bleeding at the cuts and to preserve last year’s growth where the flowers and fruit will grow. Allow a set of main branches to develop and prune laterals only enough to leave old growth for the spurs.
You can also grow mulberries as a shrub by encouraging multiple low branches to develop and only pruning to maintain growth on the lower parts of the plant.
Mulberries are generally free of pests and diseases. Cankers and dieback can occur, however, and “popcorn disease” is a rare but occasional problem. If fruits swell to resemble popped corn collecting and burning the infected fruits is advised. Other problems can be addressed by researching symptoms and remedies.
If you have space for a large shrub or medium-sized tree that produces edible fruit, mulberry might be a good choice. They will make an attractive addition to a landscape and will feed you (or the birds) with some tasty fruit over a long fruiting season starting in late summer.
Look for mulberry trees in local nurseries or find one in your neighborhood and take cuttings. Check with farmers at farmer’s markets to see if they have trees and are willing to offer cuttings. If you want to hire Margo from Sunrise Nursery to find mulberry trees for you, call her at (808) 640-9191.
Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.
Gardening Events
Saturdays: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Come with a mask and be prepared to practice social distancing. Volunteers can help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Visit the website www.amygreenwell.garden/get-involved/volunteer-1/ and sign up for the weekly email for more information on work days.
Nov. 8: “Redbay Ambrosia Beetle: Invasive Avocado Pest” from 8 to 11 a.m. Helping to prepare for this beetle by learning signs and symptoms as well as detection and management techniques. Online link: https://www.zoomgov.com/i/1609290157.
Nov. 9: “Invasive Pest Mini-Conference” from 9:30 a.m. to noon. Presenting Hawaii Dept. of Ag. Projects. Register for Zoom at https://hawaii.zoom.us/meeting/register/tjllde2oqisgE9b-E4zZ47zSu4sP6BDaECdl or contact Roshan Manandhar at (808) 274-3477 or roshanm@hawaii.edu.
Nov. 14: “Crop Insurance Programs” from 9 a.m. to noon at Ka’u Coffee Mill and 5 to 7 p.m. at Robert Herkes Pahala Gym Complex. Learn the basics of crop insurance every 30 minutes. Sponsored by Lind Insurance Services. More information at agsecure@sbcglobal.net or call 888-276-7728.
Nov. 17: “Crop Insurance Program” from 2 to 6 p.m. at UH CTAHR Kona Extension Service Conference Room. Learn the basics of crop insurance every 30 minutes. Sponsored by Lind Insurance Services. More information at agsecure@sbcglobal.net or call 888-276-7728
Farmer Direct Markets
(check websites for the latest hours and online markets)
Wednesday: “Ho’oulu Farmers Market” at Outrigger Kona Resort &Spa
Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center
“Kamuela Farmer’s Market” 7:30 a.m. to noon at Pukalani Stables
“Waimea Town Market” 7:30 a.m. to noon at the Parker School in Waimea
“Waimea Homestead Farmers Market” 7:30 a.m. to noon at the Waimea middle and elementary school playground
Sunday: “Pure Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook
“Hamakua Harvest” 9 a.m. to 2 p.m. at Highway 19 and Mamane Street in Honokaa
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu; Tuesdays and Thursdays from 9 a.m. to noon at UH-CES in Kainaliu at (808) 322-4893. Walk-in from 9 a.m. to noon Mondays, Tuesdays, and Fridays at the UH-CES at Komohana in Hilo or call (808) 981-5199 or email himga@hawaii.edu