Northern Minnesota phenology for June 2014: Blackberry


Blackberries at St. Catherine's. Flickr CC-licensed photo by Jason Merrick.
Blackberries at St. Catherine’s. Flickr licensed photo by Jason Merrick.

By: John Latimer

My first recollection of blackberries comes from August sometime in the late fifties or early sixties. I can remember the month because we were picking the berries, but the year is lost in the mists of time. I was with my brother and probably a few other neighborhood boys. The berries were no doubt sweet and bountiful. I had carefully worked my way into the center of the patch pursuing the more plentiful berries there. Anyone who has ventured into a blackberry patch knows that carefully is the only way to enter the interior.

The prickles on the blackberry are not the same as those found on the raspberry. The raspberry has many more prickles per linear inch of stem, but they are weak sisters compared to the barbs attached to the blackberry. I tell students the way to determine whether you are looking at raspberry or blackberry canes is to grasp the cane near the bottom and quickly draw your hand up the stem. If your hand is scratched and slightly red, it’s raspberry, if your hand is torn and bleeding, it’s blackberry. While I don’t expect them to conduct the experiment they quickly come to understand the difference.

So there I was carefully moving through the patch, did I mention I was wearing shorts and a T-shirt? That was the official outfit for all boys in our neighborhood throughout the summer. Shoes were optional and I don’t remember if I was wearing any or not. As I approached what my memory now tells me was the middle of this bounty, I happened to put one of my feet on a ground hornet’s nest. In a split second I had to assess which would be the more unpleasant experience, suffering the wrath of the angry hornets or tearing willy-nilly through the canes to safety. The hornets won the argument and with a few stings to get me motivated I dashed. I can still picture the damage after putting some distance between the hornets and me; dozens of tiny cuts traced my legs from thigh to ankle. It was several years before I could bring myself to enjoy the blackberries again.

June is the time of the year to mark the blackberries in your neighborhood. The plants come alight with large white flowers some nearly two inches across. The typical blackberry in the northern part of the state is well armed with thorns and grows from long arching canes. The canes are biennial with the first year canes only producing leaves. These are called primocanes. The second year canes, called floricanes, will flower and produce fruit. Most blackberry plants produce both age classes each year so there will be a mix of sterile and fertile stems in every patch.

Blackberry. Flickr CC-licensed photo by Takato Marui
Blackberry. Flickr CC-licensed photo by Takato Marui.

Welby Smith in his book Trees and Shrubs of Minnesota remarks that Rubus, the genus to which the blackberries belong, “is by far the largest genus of woody plants in Minnesota.” There are thirty-three native species and two recognized hybrids found within our borders. Looking at the range maps accompanying the text it is obvious that they are quite restricted to particular geographic ranges. Only one or two species occupy large tracts in the state. Allegheniensis and ablatus are two species that occur in most of the eastern half of the state. All other species with the exception of the red raspberry and the arctic raspberry are scattered here and there.

What this means is identifying them can be extremely difficult and for the amateur naturalist it represents a challenge far greater than the asters or goldenrods. What is interesting is the variety that may be found near your home. You may not discover their names but the habits of growth and chosen locations will provide clues to let you know that they are different from one another. In the areas of the state where the two species mentioned above can be found there are several other species that pop up. Most of them are quite restricted in range and will be different for each of us. I have a large number of allegheniensis, but I also have another species that is much shorter and rarely grows upright. I discovered it last June when the white flowers made it visible among the grasses and shrubs along the edge of my driveway. I live in the southern part of Itasca County and there are six different species here, while in the entire county there are nine different species. By the way, those blackberries that left such an indelible impression on me were R. allegheniensis.

From the phenology notebook:

June 3, 1997      There is a knee-high plant blooming in the ditches today. It has tiny white flowers and belongs to the Brassica family that includes the wild mustards and winter cress. Hairy rock cress is one of the first plants to bloom in the ditches and dry places. Move into the forests where things are cooler and shady and the starflowers are blooming. Seven sharp pointed white petals make these flowers look very much like stars. Flowering wintergreen are blooming and in a couple of months they will bear small red berries with a wonderful wintergreen flavor. The first of the migrating monarch butterflies have returned today.

June 16, 2011     I see my first white admiral butterfly today. Some of this species migrate into Minnesota from the southeast while others develop right here from eggs laid the year before. High bush cranberries have begun to bloom. Look at the flowers and you’ll notice that there are large four petalled blooms surrounding a cluster of smaller white flowers in the center. These large flowers are sterile and serve only to attract pollinators to the fertile flowers in the middle.

June 30, 2008     The first flowers of the Indian pipe are up and a pale pink in color. As they mature they will shift to nearly white. That is, the whole plant will shift because this is a plant without chlorophyll. It is a saprophyte, a plant that steals its nourishment from its neighbors. The blackberry flowers are approaching their peak of bloom. They are large white, five-petalled flowers some nearly two inches across. The wild irises in the swamps are nearly done blooming for the year. White campion is approaching peak bloom. It is a night flowering plant that uses a sweet perfume to attract moths that will do the pollinating.

John Latimer is well known throughout northern Minnesota for his phenology work.  John appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. We hope his work will be a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Journal.  It is printed with the author’s permission.

The University of Minnesota Extension Forestry team.

You may also like


  1. What is the status of the Monarch butterfly? My beautiful bed of Milkweed may go untouched again this summer. Two years ago and earlier the larvae stripped most of the leaves off. Last summer I saw neither adults nor larvae.
    Have they joined the fate of the passenger pigeon?? bok