Birds have been planting blackberries vines throughout my back yard. The plants are coming up through the plants and are a pain to get too. I thought I had eradicated the plants last year, but they came back more vigorously this year. After hearing different advice from various "helpful" friends, I need to know what are the most effective methods of getting rid of these plants for good.
I'm not sure what specific advice, you have received; hence, I can't give any pros and cons on the suggestions. So, I'm going to address the problem from an overall perspective.
First off, there are no quick or "one and done" answer(s) to this problem.
Your options of eradicating and undesirable plants growing within desirable plants is minimal. There is no chance of eradicating the problem this year as the growing season is nearing an end. There is a very good chance you'll be dealing with this problem next year at this time. It's a war of attrition.
Blackberries spread rapidly by above and below ground rhizomes; hence, they're difficult to control. I'd manually remove any shoots near the crown of the crown or base of the plants or primary surface roots. For the rest, I'd repeatedly spot treat the new shoots with the herbicide, Brush Killer, being careful not to spray the foliage. You have to be very persistent in resolving this issue
Last year I chopped down a birch tree that was infested with termites. The tree stump was grinded down, but I noticed that there are still roots in the ground, and the ground is sinking. Will the roots grow back? A home improvement center recommended a chemical that kills roots in pipes. It says it will kill new root growth. Besides, should I fill in the potholes with sand and rock? The uneven surface makes it difficult to mow the lawn.
Birch trees are not known to send up sucker so I wouldn't be concerned.
It's a bad idea to apply a liquid 'root killer' to the open ground. They're very caustic chemicals made for enclosed cylinders where water can wash them away. Besides, it's a moot point, as the old roots are not going to rejuvenate themselves. They'll continue to decompose over time.
Filling in the holes is pretty straightforward; however, I wouldn't use sand. Sand in time will filter through the soil layers creating another depression.
You could use the rock as filler in the larger holes and then finish off with, potting soil, planting mix, or homemade compost. You should first moisten the material and then tamp it down several times. You want a substantial base.
Also, I'd use a two by four to grade the high and low spots to help with unevenness.
Once the area has been leveled and graded, you can then reseed the bare spot with Scott's E-Z Seed. Scott's EZ seed is a combination of seed, fertilizer, and absorbent growing material. Reseeding has never been this easy.