The leaves remind me of wattle bushes (Acacia spp). Have you seen it flower?
I don't know of any websites, but in Australia at least you can send a specimen to the local botanical society and they'll ID it (usually for free). Is there perhaps a similar place you could look in your local area, maybe a local college?
I agree...it's almost certainly an Acacia. A quick internet search of Acacias common in cultivation and as invasives in southern CA should turn it up. Flowers and/or seedpods will be useful diagnostics.....
Location: Grand Valley of Colorado's Western Slope
posted 4 years ago
well, I am not familiar with acacias, but my first thought when looking at the twig you are holding is mistletoe.... crazy thought. I've never seen mistletoe grow in a hedge or thicket as in your first photo, and the leaf is not right either, so no telling why I thought that.
I notice the veining in the leaves is distinctive, it probably has a central vein and branching side veins but they are not predominant. Flowering would tell a lot more. If you have master gardeners in your area, or an ag extension office, they could help. Often the people at nurseries are big plant people, and might know. If you have a university near by, you could call and see if they have botanists who are willing to help if the other methods don't yield any good answers.