Average crown spreads for Quercus rubra over 100' reported from Michigan but that state has become home to multiple suspiciously large tree dimensions. Out here in this part of significantly milder USDA 8 multiple crown spreads over 100' have been measured by careful workers. The majority of these records are from Seattle but one red oak in Tacoma averaged 124' across in 1990, another in the same park 117' the same year.

We have a black walnut tree, and I absolutely cannot stand that thing! LOL! It is the last thing to leaf out in spring, the first to drop them in fall, and we were picking up walnuts daily for at least two months last fall! Blech! That tree's days are numbered, I tell you!! One of my dogs once got a black walnut stuck between his back teeth. It was lodged in such a way that it propped his jaw open and he couldn't close his mouth. :( I saw him walking around the backyard, drooling and holding his mouth open, and thought he must be having a seizure or something. Scared me to death! Toxic plant reports can be very confusing. I have run into a lot of what you mentioned with the hosta: One site says OK, the other says no way. :( I've really been pulling my hair out over it! I finally broke down and bought a super-expensive, but well-regarded, book about toxic plants, in an attempt to get to the bottom of it all. One thing I have gleaned is, there are all ranges of "toxic," from upset stomachs to death. There are a few plants that I can say with certainty I would never, ever, under any circumstances have in my yard. Then there is the category of plants for which I have not been able to find one report of toxicity. Like the highly toxic category, it's pretty small, too. These are the ones I'm sticking with in my yard. Most plants, it seems, fall somewhere in between. Toxic properties, but varying reports on the graveness of the toxicity. It is extremely difficult sometimes to determine to what degree they are toxic. Anyway...I think it's awesome that you are such a great dog owner, to be concerned for their safety. :) They are lucky dogs to have you!

Have not seen this echibeckia but have heard of it; is it like a orange /yellow coneflower? There is a white spike speedwell, called icicle I believe. I didn't snap it up sometime ago when I saw it and haven't come across it again. I love love Royal Candles, Red Fox is nice too but more subtle. Boltonia is one I would love but no room! I've found a few sale plants that had to come home with me: a primula, a dark pink dwarf aster, Moonshine Coreopsis, a pale yellow globe flower, Angelina sedum, and a variegated Fallopia that I do not trust not to be invasive so will grow in a container. I just can't resist those sales even though finding a place for these plants will be a challenge!

Some of your plants are not as drought tolerant as others so placement of those and the ability to water as necessary is critical. In particular, the echinacea (coneflowers), penstemon and the May Night salvia are thirstier than the others. Also the kangaroo paws vary in their water needs - some species/cultivars are more DT than others. The BeWaterWise or California Friendly Gardening programs are great resources for you. I've linked to one resource for Orange County that may be helpful. Be sure to take some time to go through the photo gallery........there are some stunning xeric gardens included that you can use for inspiration as well as to gather some tips for placement. While you don't necessarily need to be restricted to natives, they are a great source of plant material to select from, being both ideally suited to climate as well as having low water needs. And they are generally colorful, attractive to wildlife and not much bothered by pests or disease issues. Any lavender will work and they are pretty commonly found in most nurseries - both English and Spanish lavender are great xeric plants and put on a long lasting flower show but I wouldn't spend a lot of lime looking for so-called "colored" varieties (lemon lavender very blah in flower - hardly noticeable). Other plants I would consider including are California fuchsia (Zauschneria californica, aka Epilobium canum), manzanita (Arctostaphylos species), California lilac (Ceanothus), Salvia greggii, S. jamensis and Justicia californica. byw, Rogers Gardens in Corona del Mar is an excellent resource for this type of project. You might also get some very good feedback on your plans in the Californium Gardening forum.