Its trunk or stem has hard wood, smooth and ash-gray bark and thorny branches. The small, shiny leaves are dark green on top, light bluish green underneath and have three irregularly toothed lobes. The white flowers have round petals. Hawthorn is used internally for circulatory disorders and most heart problems, and especially if you have a feeling of tightness or pressure in the heart area. It is also helpful in restoring high blood pressure to normal, and combined with Ginkgo biloba to boost cerebral circulation and improving memory.