Burdened by the common name of Deerweed, Margaret Huffman of the North American Butterfly Association calls this lovely Lotus “the best butterfly plant for Southern California.” The Orange Sulfur, Gray Hairstreak, Funereal Duskywing, and several others use it as an all-important larval food plant.
It is also much-loved by several types of bees including our favorite, the Yellow-faced Bumblebee (Bombus vosnesenskii - click here for an enature.com profile). The flowers change color from yellow to red once visited (see photo), signaling a bee to try a fresh bloom (bees see red flowers as black).
The thinly-leaved branches arch up and out, forming an airy mound up to 3' across in time, but usually smaller. It is capable of taking full sun and no supplemental water once established, although we have plants thriving in a variety of settings including partial shade and semi-regular water. Known to go semi-dormant and occasionally short-lived, we're always growing* extra plants to use both as specimens and to stock out-of-the-way places we suspect butterflies might visit. Despite its name, our deer are yet to eat it.
We also highly recommend Lotus dendroideus var. dendroideus (Island Deerweed) if you can find it (we bought ours originally at the Santa Barbara Botanic Garden nursery). It's a handsome, woodier plant with larger flowers that smother the branches in summer. We observed a Gray Hairstreak egg-laying on it, so it passed the butterfly test.
* Propagation: You don't see deerweed for sale in many nurseries; probably because it has a tendancy to be short lived (we've had some die off in 1 gallon containers before they even got planted!). Deerweed is relatively easy from seed started in the spring, but it can be finicky when transplanted as seedlings. We found it does best after it's been neglected in a seed tray and is starting to develop a woody base (though others have said the secret is to transplant early, when the seedlings have just a couple of leaves). Usually we seed Deerweed directly to 2" rose pots (we put sterile seed mix on top, potting mixture in bottom). Not all seeds will germinate, so try 2–3 seeds per pot. We move up the successful ones to 4.5" and then out in the ground as soon as possible. When collecting, the seed is ripe when it's brown and dry and literally falls off the plant when touched; because the seed falls off so easily, we collect the seed over a period of weeks as they mature up the stem. We've never seen birds eating the seeds off the stems.