- Bitter almonds are native undomesticated almonds, which were gathered in the wild for thousands of years before domestication. Bitter almonds contain glycoside amygdalin, which when crushed, ground or chewed becomes cyanide. Bitter almonds must be soaked and blanched like acorns before being eaten.
- Sweet almonds are domesticated almonds, prized for their delicious seed (almonds are not truly nuts), essential oils and superb nutritional value. Cultivated sweet almonds are classified by their blooming time and whether they self-pollinate. Most almonds require two varieties of almond planted together (in the same hole if necessary) to cross pollinate each other and set fruit. A few varieties are self- pollinating and can be planted alone.
- Early-blooming varieties should be grown in warm areas where there is no danger of frost. Cultivars that bloom early and should be planted together for cross pollination include: "Nonpareli," "Price," "Ne Plus Ultra" and "Neplus."
- Late-blooming varieties are the best option for areas where frost is a hazard. Cultivars that bloom late and should be planted together include: "All in One," "Mission" (or "Texas"), "Hall," "Titan" and "Butte." Early-flowering varieties can also be planted with late-blooming types to help initialize pollination.
- Self-pollinating varieties do not need a separate pollinator, so they can be planted alone. Self-fruiting varieties include: "Garden Prince," "Hall' (partially self-fruitful), and "All in One" (self-fruitful, and a great pollinator for other late-blooming trees).
