I agree wholeheartedly with tiffy (and by the way your gardens look wonderful). Mulch serves many purposes in the landscape and one should not overlook its use in this day and age when drought and water restrictions are in the news all the time. If you are lucky enough to live in an area where water is not an issue now or where mother nature is currently supplying you with sufficient moisture so that you don't have to irrigate, that is nice. But with changing weather conditions, you might never know when all that could change. Mulch helps prevent water evaporation and your need to apply it to keep your flowers and plants looking good. It decomposes over time to improve the soil structure to help the soil hold onto the moisture it does get. It is readily available by collecting fallen leaves, community giveaways by those cities that collect fallen leaves and then compost them and either give it away or sell it, and often tree trimming companies will give chipped wood away for free (my local utility company gives it away free when they clear limbs from the power lines). I for one would not consider a garden complete without a nice layer of some type of mulch to conserve moisture, improve the soil, and keep weeds down. Too me it would be like going out into public wearing loads of jewelery without any clothes on! LOL

I just discovered them. I put some of the trailing kind in the garden and kept some in a hanging basket. I like plants that volunteer. So, that's good news to me.

I figure I could add something years later since other people added comments a year later. I moved into a rental house in Boulder, CO that had very well done perennial beds around the time this original post was written. It's been neglected for 7 or 8 years or so, especially the last 3 years. I can tell from Google maps the last year the lambs really took out for the rest of the beds and even the yard. I've been digging, pulling and now have covered an entire bed with clear plastic to kill the seeds before I'll consider planting there. The roots have formed an impenetrable mass and are sometimes thicker than my thumb. They have smaller roots finding them all together. I think if I were building a prairie Sod house I would be thrilled to find these. I'm constantly facing masses of sprouts and churning them over with hopes of killing most of them. We live in a Bee Safe neighborhood, and I don't think Round Up would have helped much anyway. I put an ad on craigslist and I've had many people haul garbage bags of plants away but eventually I got tired of answering the text-I think I had probably 50 people take A wavering amounts of these plants. I've never had them spread before but I stay on top of them, possibly since I use them in flower arrangements or pull them out as soon as they stray out of their designated area. I've discovered I now despise them and I don't think I'll ever let them grow again. I see them downwind from our yard and I'm tempted to go pull them now to spare them future agony- especially since it's likely the seeds came from here in the first place.

Thanks for both the replies. I might try planting some salvia and see what happens (although I wasn't sure salvia can do well with lots of shade). As for what's eating my impatiens, I definitely saw a critter's tail as it ran out of my impatiens planters, on two different occasions, when I turned on the backyard light at night, and it was either a rat or possibly a possum (or a large mouse!). As I'd noted, this was the first year that ANY critters have eaten my impatiens (or any other flowering plants) down to the soil, and I'd also seen a rat in the winter eating my tangerines (and I did research on what would eat a tangerine by hollowing it out and eating the insides, and the answer was rats). I live in a townhouse complex and some of us have ivy in the front or back yards and my neighbor whose yard is attached has a whole row of giant Italian cypress, and I think rats hang out in both kinds of plants. So I'm not sure what I can do to keep rats or other rodents/vermin out of my particular yard, although I'll do some further investigation into city or county resources or pest companies. My back yard is way too small and urban for bigger animals (like deer) to get in, so I think whatever is eating the flowers must be something in the rodent family. I did find an online post about rats eating someone else's impatiens, so that seemed to confirm my unfortunate sense that I've got a rat (and I would like to think I only have one--but that's not realistic). There's no garbage or even compost in my backyard, by the way, or pet food. Perhaps the Bay Area's common roof rats have gotten desperate for food or moisture and so are starting on flowering plants!