How to Grow Thimbleberries ~ for Food and Medicine

Thimbleberries, also known as flowering raspberries, look quite a bit like raspberries when the fruit is ripe.  Thimbleberries have a very soft texture and intense taste.  To me, they taste more like raspberries than raspberries.  The best way I can describe the taste of thimbleberries is like raspberry flavored candy.  It’s like someone wanted to make something raspberry flavored, but they dumped too much raspberry extract into the batch.

The berries themselves are soft and fragile.  They begin to spoil literally hours after harvest, so you won’t ever see them in the grocery store.  That’s all the more reason to grow them yourselves.

Though the fruit may look similar, the plants and flowers are different and need different care than traditional raspberries.

Thimbleberries (Rubus parviflorus) are native to much of the United States.  The plants grow along woodland edges, roadsides and railroad tracks.  I first ran across them growing in a very intentionally planted native bee garden along a stream in my backyard in Vermont.  The flowers are beautiful, and they grow at head height on gigantic 6 to 8-foot tall arching canes.

How to Grow Thimbleberries

Thimbleberries will grow from seed, and they’re commonly spread in the wild by birds.  To start thimbleberry seeds, you need to mimic their natural environment and scarify and cold stratify the seeds.  Scarification mimics a bird’s digestive system and helps to slightly damage the seed coat, which will stimulate germination.  You can do this by pulsing them in a blender with a bit of water.  To cold stratify the seeds, place them in the freezer for a few months before planting.

Since scarification and stratification can be a bit taxing, it’s more common to start thimbleberries from cuttings or dormant rhizome divisions.  They form rhizomes under the soil and can be divided every few years to establish new plantings.

Thimbleberries are large plants, growing 6 to 8 feet tall and about 3 feet wide.  Allow ample space between plants.  If you’re planting them in rows, leave 8 feet between rows and 3 feet between plants.  The plants will spread by rhizome and fill in the rows quickly.

A cluster of thimbleberry flowers and unripe fruit. The canes bear continuously until the first frost, so they’re always putting out new flowers as the fruit begins to ripen.

Thimbleberries like continuously moist but not soggy soils.  Mine have always grown best at the edge of drainage ditches, streams and near the dripline of my house where they get plenty of water.  They would be a good choice for planting in a rain garden.

As a wild plant, they don’t really require fertilizer.  Commercial fertilizers can actually damage the thimbleberry canes.  If you do add compost, be sure that it’s well decomposed.  Compost that is too fresh and still decomposing can damage their roots and actually cause their roots to compost right along with the other material.

Unlike raspberries, thimbleberries do not need trellising or pruning.  Let them grow wild and free for the best production.

Foraging Wild Thimbleberries

Thimbleberries are easy to identify in the wild.  The leaves are large and soft, shaped a bit like a 3 pointed maple leaf.  Though the fruit may look a bit similar to raspberries, the leaves are very different.  Raspberry leaves are small and come in groups on the branch.

Note the differences between a raspberry leaf and a thimbleberry leaf. The raspberry is on the left with multiple small leaves, while the large 3 pointed thimbleberry leaf is on the right.

They grow on tall canes without thorns.  The canes have a brown “bark” that tends to fray as the canes grow, revealing a white under color.

A thimbleberry cane. Note the lack of thorns, and the characteristic peeling brown bark.

The flowers are a dead giveaway.  Most people probably haven’t paid that much attention to raspberry flowers, but that’s because they’re not that noticeable.  The bees find them for sure, but they’re not that impressive to humans.

Note the differences between a raspberry flower (left) and a thimbleberry flower (right). There’s a reason they call thimbleberries flowering raspberries.

The berries themselves look like raspberries, but wider and flatter.  A single thimbleberry will fit over your thumb, whereas raspberries tend to have smaller cavities and be more pinky finger sized.

Wild thimbleberries are sweet and tasty and great for eating out of hand while on a hike.

Thimbleberries and Wildlife

Thimbleberries are a favorite of the bees, and you can often find many bees ecstatically thrashing around within the same flower.  The plants themselves are a host nursery for a really cute honey bee mimic moth, called the yellow-banded sphinx moth.  The moths are a type of hawk moth, that looks somewhat like a tiny hummingbird or bee.  You’ll be confused when you see them, and I can’t help following them around when I see them in the garden.  They’re a great curiosity for both kids and adults alike.

Four native bees all in the same thimbleberry flower. A common sight in mid-summer. They’re also a favorite of large bumble bees since the flowers are large and accessible.

How to Use Thimbleberries

Since the fruit is so soft, it almost always becomes bruised during harvest.  The damaged fruit begins to spoil within hours.  The best way to enjoy them is fresh in the garden, popping them straight into your mouth.  If you have a particularly large crop, thimbleberry jam preserves the flavor.  The jam is famous in Michigan, and I recently heard a radio program (The Splendid Table) that suggested using it to glaze a baked ham.  Try adding them to a vinaigrette for a tasty dressing or marinade.

Beyond the edible fruits, the fresh shoots are edible in the early spring, and the leaves can be made into a tea.

Medicinal Uses of Thimbleberries

When I first spotted thimbleberries, I really had no idea what on earth I had growing in the yard.  The only identification book I had at the time was a wild medicinal plants book, so I flipped through and happened to find them.  They’re medicinal!

They have been used by Native Americans for centuries.  The berries are rich in vitamin C.  A poultice of the leaves is used to treat burns and wounds, and even other smaller skin related issues like acne.  The roots are made into a tea for treating digestive ailments such as nausea, vomiting, diarrhea and dysentery.

For a more practical everyday use in the woods, the leaves make a great toilet paper.  They’re large, soft and soothing to the skin.