On 364 days of the year, I consider this a pesky, invasive weed.
Today: It's all about shamrocks!
Name: Creeping woodsorrel, Oxalis corniculata,
Leaves: Three heart-shaped leaflets which open and close in intense light and at night.
Bloom: Five small yellow petals atop of slender and tender stalk.
Growth Season: Year Round (!) No wonder this weed gets such a strong hold on my hill side.
Reproduction: Creeping and rupturing seedpods which can expel between 10-50 seeds.
Locations: Turf, ground covering, gardens and most annoying between pavers!
Source: UC IPM Online
