This was exactly my problem in 2006. I renovated the entire backyard in 2005, but some low spots developed and water puddled there and the seeds rotted. In July of 2006 this is what I had... lots of crab grass.. So in August I hit the CG and weeds with RU. Mowed it real low once the CG was dead. I bought some loam with compost in it and spread about an inch or 2 in the low spots and seeded. I just dragged a rake over the seeds to cover them a bit and rode tractor wheels to set it up nice. This is what it looked like in October OK, now the results as of 8/14/2007?

If it's organic there is always a way to compost it but the real answer depends on how aggressive and talented a composter you are. With a truly hot pile you would probably be o.k. but much caution is otherwise required. Some of the plants you mentioned are very invasive so preventing their spread is your concern more than making compost. For those that are not in seed and can be killed in place (smothering, etc.), I would be tempted to just leave them be after dispatching them (except the really brushy stuff like privet which you will want to get out of the way and chop up). Plants not in seed and that don't have really tough roots or rhizomes are probably o.k. on a cold pile but, again, my experience with invasives is that you should be more concerned with their eradication than putting them to use. Ailanthus is a bit alleopathic. Uprooted vinca would either have to be hot composted or allowed to dry out and die before adding to a cold pile. Vinca clippings without roots would probably be safe on a cold pile. With invasive plants such as these, I tend to let them dry to death off the ground and then throw them back on the ground or in my cold bins. You might want to check out the natives forum and also the management profiles offered by The Nature Conservancy for more advice on how to get rid of these plants.

Hmm... I'm not sure about that. Do you mean spent flowers from this season? As far as I know, mulberries and sweetgums do not grow in my region. We have tons of oak trees (and tons of acorns) but I'm really not aware of what oak tree flowers would look like. I should mention that currently virtually nothing is "up" yet here - there are very tiny buds on trees, the hosta tips are just barely visible above ground, the grass is getting greener but not very green yet. There are definitely no spent flowers from THIS year yet, as there are no tree flowers at all yet. My planted eupatorium are not doing anything yet, but I wasn't sure if loose seeds would somehow sprout into something larger if they were above ground. I know... very ignorant. :-) But what is so mysterious is the fact that there are not yet flowers or leaves on any of our trees, so it can't be anything from this year.

We have them too and they are awful. We used a certain weed killer (I can't remember what), as suggested by Home Depot, so no more will grow. However, We still have all the dead ones all over. I did some research and found this: http://answers.yahoo.com/question/index?qid=20061004214319AA4NZ2D It says what to use to kill them, and what to use to get them off the lawn once they are dead. Good luck!