One of the best extra large flowers in a blend of deep rose, salmon, cream, pink, scarlet, white, mid blue, and crimson. Sow Mammoth Blend sweet pea seeds for the earliest sweet peas to bloom from late spring to early summer. Direct sow sweet pea seeds at three-week intervals for an extended bloom period. They have very large flowers on long stems, so they’re a great cut flower. Their scent is more subdued than other sweet pea varieties.