Sorry Ally, barberry IS invasive. Look at vtinvasives.org/invasive/japanese-barberry. Maybe your soil is not conducive to spreading where you are but they are in my area. I prefer to not spray poisons on my plants and birds are a big part of the problem as they disperse the seed.
Barberry also competes with wild blueberries and steals nutrients from them with there larger and more aggresive root systems.
As far as harboring a vector for Lyme, well this is so important, life changing that I take this seriously. I've had Lyme for 8 years, believe me, you don't want to get it. New information is that DEET products are much poorer than thought to repel deer ticks.
Yes the ticks are so small that chances are you won't see them, they often crawl in places you cant see,..only 50% of people that bulleyes rash.Best blood tests are perhaps 60-65 % accurate for a positive , leaving a lot of people falling thru the cracks. Also if you don't find the tick and it has been attached for more than 36 hours, you probably now have to face chronic Lyme. Its been said to people who say "I HAD Lyme" that, no, you HAVE Lyme,..it may resurface months and years later.
Mice are the big vector for carrying deer ticks.
I've run into 3 people one was DXed with MS and the other 2 was DXed with ALS and was found to have Lyme instead! The ALS pts were sent home to die and perhaps would have if someone hadn't pushed them for aggressive Lyme treatment.
Ever watch that show "Monsters Inside me"? Just today they had a segment about Lyme and another co infection babesesia that is also carried by the the same deer tick. These ticks can carry a number of other diseases, lots of anaplasmosis from them around here.
There are a number of other plants with berries that birds actually prefer. Small birds escaping from hawks can use any dense bush, A hawk can't fly into most dense bushes.
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