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Phenology report: Blackberries and raspberries in bloom

A tricolored bumblebee visits a blackberry flower at Long Lake Conservation Center near Palisade, MN on June 15, 2024.
Charlie Mitchell
/
KAXE
A tricolored bumblebee visits a blackberry flower at Long Lake Conservation Center near Palisade, MN on June 15, 2024.

KAXE Staff Phenologist John Latimer provides his weekly assessment of nature in Northern Minnesota. This is the week of June 18, 2024.

Can you tell the difference between wild raspberries and blackberries? If you judge by the colors of the fruits, you might be misled: the fruit from the most common of Minnesota’s raspberries is black, not red.

Luckily, right now is the most risk-free time to identify them! John has spotted them flowering in Northern Minnesota. Get out and enjoy - you can't get poked by the thorny, bristly stems just by looking at the flowers! (Though a mouthful of berries is definitely worth the risk.)

Below the "Topics" section, you'll find a guide to distinguishing between our most common blackberry and raspberry species (and a photo guide). Let's get ready for a great picking season!

Topics

  • Introduction: (0:00-1:02) 
  • Lake Nipigon (1:02-6:17) 

    • Location and geology (1:02-3:34) 
    • Plant and animal communities (3:34-6:17) 
  • Plant development (6:17- 9:37)

    • Raspberry and blackberry flowers (6:17-7:17) 
    • Smooth rose flowers (7:17-8:26) 
    • Nannyberry, chokeberry development (8:26-8:53) 
    • Blue flag iris flowers (8:53-9:01) 
    • Maiden pink flowers (9:01-9:37) 
  • Eagle nest developments (9:37-10:39) 
  • Conclusion (10:39-8:47) 

Befuddled by berries?

The three most observed blackberry and raspberry species in Minnesota are, in order: the black raspberry, the wild red raspberry, and the Allegheny blackberry. (I’m ignoring the dwarf raspberry here, since it’s easily distinguished by its small size.) Here are three ways to tell them apart, plus a few photo guides for reference.

Identify by flower

Can you see the flowers from a distance? If yes, it’s probably a blackberry. (Blackberries have flowers anywhere from 1-3 inches wide, with much more showy petals.)

If the flowers are small – 0.3 to 0.5 inches wide - it’s probably one of the raspberries.  

To tell the difference between red raspberries and black raspberries, look at the petals. Red raspberry petals stick forward, surrounding the pollen-bearing stamens and pollen-receiving pistils, while black raspberry petals emerge sideways to frame the pollinating portions. Red raspberries tend to lose their petals more quickly than black raspberries. 

Identify by fruit

Red raspberry fruits conveniently look exactly like the ones you'd buy in the store, though they tend to be smaller and more flavorful. When picked, they easily separate from the stem and receptacle, leaving a conical hollow on the inside. 

Both black raspberry and blackberry plants produce black berries. True blackberries retain part of the stem (called the receptacle), and are not hollow. So, unless you chew it like a tiny corncob, each blackberry will come with a little bit of green plant material in the center. 

Ripe black raspberries, in contrast, are pulled off the receptacle, leaving a small hollow inside. A bite of raspberry, whether red or black, is solely comprised of fruit. 

 A composite image shows side-by-side comparisons of blackberry, black raspberry, and red raspberry fruits. The blackberry fruit, labeled 1, has a green center. The red raspberry (2) is red, with a hollow center. The black raspberry (3) is black with a hollow center.
Charlie Mitchell
/
KAXE, with original images from iNaturalist users saulih, shelby555, and Kitty Maurey
A side-by-side comparison of the fruits of blackberry (1), black raspberry (2), and red raspberry (3) plants.

Identify by stem

If there aren't any pretty flowers or tasty berries available, you can still figure things out. First, examine the stem from its base to the tip of the plant. Look for hairlike bristles and thorny spines.

If it only has thin bristles (the kind that irritate your skin, but wouldn't typically make you bleed), you’re looking at a wild red raspberry. Bring some anti-itch cream. 

If the plant only has large, broad-based spines (the kind that would certainly make you bleed if you pulled on the stem), you’re looking at a black raspberry. Move carefully.

If it has both - big spines on the stem and a few thin bristles at the branch tips and flowering stalks - you’ve got your hands on a blackberry plant. Be gentle!

A comparison shows the differences between blackberry, red raspberry, and black raspberry stems. The blackberry stem, labeled 1, has both small bristles and thick pointy spines. The red raspberry stem, labeled 2, has only long bristles. The black raspberry stem, labeled 3, has only long, sharp, pointed spines.
Charlie Mitchell
/
KAXE. Original images from Charlie Mitchell and iNaturalist users fulto006 and ondich.
The blackberry's stem, labeled 1, has both small bristles and thick pointy spines. The red raspberry's stem, labeled 2, has only long bristles. The black raspberry'sstem, labeled 3, has only long, sharp, pointed spines.

Do you have a favorite berry patch? Let us know: email us at comments@kaxe.org or text us at 218-326-1234.

That does it for this week! For more phenology, subscribe to our Season Watch Newsletter or visit the Season Watch Facebook page.

Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).

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Charlie Mitchell (she/they) joined KAXE in February of 2022. Charlie creates the Season Watch Newsletter, produces the Phenology Talkbacks show, coordinates the Phenology in the Classroom program, and writes nature-related stories for KAXE's website. Essentailly, Charlie is John Latimer's faithful sidekick and makes sure all of KAXE's nature/phenology programs find a second life online and in podcast form.<br/><br/><br/>With a background in ecology and evolutionary biology, Charlie enjoys learning a little bit about everything, whether it's plants, mushrooms, or the star-nosed mole. (Fun fact: Moles store fat in their tails, so they don't outgrow their tunnels every time conditions are good.)