On Sunday, I posted about Ken Thompson's new book, The Book of Weeds, and it drew a lively response.

Among the comments was this one from Patricia: "My daughter recently bought a home whose yard had been professionally landscaped.  One of the first days I was there she wanted to start pulling what she thought were weeds.  I tried to help a little but found myself seeing plants that I was not sure were weeds at all.  She said yesterday that she fears she pulled plants out that weren't weeds and left in the ones the were! 

"Obviously, "you can't judge a book by its cover" when figuring out what are weeds and what aren't."

Imagine my surprise when I found this missive from Thompson himself in my e-mail box. I will let him take over from here:

"Hello, I'm the author of The Book of Weeds. Despite writing about weeds, I'm only just beginning to realize the confusion they cause to many gardeners, and I was moved by Patricia's plea on behalf of her daughter: is it a weed?

At this distance (the other side of the Atlantic) I can't really help, but here is some general advice: any plant that seems to be making itself too much at home, or even bent on world domination, is probably a weed.

 But if you really have no idea what it is, there's no harm in leaving just one until it flowers, or someone else turns up who can identify it. Then you can either finish it off (if it really is a weed), or keep it if it isn't (and if you like it).

Given its previous behavior, you will soon have plenty more if you want them!"

Thanks, author Thompson. Isn't that what they say about weeds? They are perennials you don't want.