Surviving brushes with death

Cutting, digging or burning doesn't stop this plant.
SCRIPPS HOWARD NEWS SERVICE
In pies, jellies or fresh off the plant, blackberries are pure pleasure. But they lose their charm on a thorny plant mass that's taking over your property.
A blackberry plant is a prickly, pushy adversary. Mowing, burning -- even bulldozing -- won't faze it. Such strategies cut it down to size, but the plant soon re-sprouts.
Brutalizing a blackberry bush only invigorates it. The best way to defeat invasive blackberries is to be more persistent than they are, says Larry Forero, livestock/natural resource farm adviser for the University of California Cooperative Extension in Redding.
"The thing that just amazes me is how quietly invasive they are," Forero says.
In for a fight
If you have vigorous, expanding plants and you want to get rid of them, you'll be in for a fight.
"There really are not very many effective options," says Joe DiTomaso, a weed specialist with UC Cooperative Extension in Davis and a member of the California Invasive Plant Council.
Digging out plants is difficult. "You have to get every piece of the root or it comes back," DiTomaso says.
Mowing stimulates suckers and encourages more branching, according to the UC Integrated Pest Management Program's Pest Notes on blackberries. "If you cut it down, it just comes back with a vengeance," DiTomaso says.
Burning encourages the plant to re-sprout from rhizomes (horizontal underground shoots). And bulldozing spreads the plant by fragmenting the roots and stems, which then re-sprout in new locations.
The UC handout says repeatedly tilling the ground ultimately brings success. While rototilling once will fragment the rhizomes and spread the plant, repeatedly tilling eventually eliminates it.
Herbicides
Herbicides are another option. Glyphosate (Roundup) and triclopyr (Brush-Be-Gone) are available for home use. The best time to apply herbicides is when plants are moving sugars (produced through photosynthesis) from their canes to their roots, Forero says.
Don't spray when plants have fruit that people might pick and eat, DiTomaso says. But don't wait too long either. When leaves start falling and the plant begins to shut down for winter, herbicides aren't effective. Herbicides are not recommended for drought-stressed blackberry plants, DiTomaso says. Those plants have shut down. If a plant's not active, herbicide won't move through it.
Applied at the right time, herbicide should kill much of the plant. Hit the sprouts that pop up the next year with herbicide, DiTomaso says. Eventually, the plant should succumb.
It's important to use the herbicide concentration stated on the label, Forero says. A higher concentration doesn't result in more kill, just more expense. "It makes sense when you use this stuff to read and follow the instructions," he says.