Why Are There Evil Weeds?

A few days ago, I attempted the impossible! I decided to plant a (very) small garden in the back yard with my 2 brothers...not so brilliant of me! I started by sending C1. to gather sticks to put aroud the edge of the garden and C2. decided that he would help out by picking up all the earthworms and cutting them in half with my spade. We eventually got to the point of planting the bulbs and C2. wanted to know why we were burying things and felt like he needed to get them out because, just maybe all this heat was getting to us. We finally did the last of the bulbs and after about twenty minutes of repeating "C2., don't step in the garden honey..." C2. says " Is dirty, my hand is dirty...worm is dirty-I get 'im out " we were able to start putting up the stick border so D. wouldn't mow over the flowers.
During all of this I was explaing to C1 that we had to watch out for 'evil weeds' and make sure that they didn't take over our flowers. When we walked away to go eat dinner (and wash up) C1. said, " K2., why did God make evil weeds, I thought He said the earth was good, and evil weeds aren't good." I responded, " Well in the begining it was good, and everything was perfect. Then Adam and Eve disobeyed God by doing something very naughty and God cursed the earth because of it. That is why there are thorns, cactus' and other 'evil weeds'. You know how when we do something bad and M. and D. punish us? Well God loved Adam and Eve and they had to be punishd too, that is wjy there are 'evil weeds'."
This is true but it comes with reassurance. Those that have repented and put thier faith in Jesus to save them from Hell have the assurance of a New Earth. I look forward to the day without and 'evil weeds' and the day when I can glorify my Savior without any blemishes of sin. Do you?
Katie