Well, here in Germany its not illegal to buy or sell property, as far as I know. However, things could be delayed, since many municipal offices are closed or work on a "home office" base. Same as lawyers, too.
Flower seeds are still available in DIY Markets which are still open with certain rules of keeping distance between people. And you can mail order them, I guess.
Fishing and hunting is not allowed in Germany anyway, Corona or not. Unless you have special permits. A fishing permit is not too difficult to get, but one for hunting is a real task. You need to do extensive learning on wildlife, protection regulations and so on. And then you need to get a weapon permit as well, which is always a problem here.
If you have all that, I can't see why someone is denied to sit alone at a river bank, or sneak around in a forest which you usually have to rent if you want to hunt - you can't just go into any random forest.
Mostly the current restrictions are aimed to keep people from gathering. Sports events, concerts, restaurants, pubs, all the places where people come together are closed.