How Often Does a Pecan Tree Bloom?

Bloom Maturation Pattern

• Pecan trees are broadly divided into protandrous and protogynous tree types based on general bloom maturation patterns. On protogynous pecan trees, female flowers mature first. Male pollen is not released until female flowers are no longer receptive. On protandrous cultivars, male flowers consistently mature first. The pollen from male flowers matures and is released several days to a week before female flowers are receptive. As a result, while both male and female flowers are present on the same plant, the slight delay in maturation severely limits self-pollination opportunities.

Flower Structure and Pollination

• Male flowers, called catkins, are multi-lobed fluffy projections that appear on the prior year's wood. The catkins transform from green to yellow while pollen is released. After pollen is shed, the catkins turn brown and drop from trees. Star-shaped pistillate female flowers are borne on the end of new growth. On the tip of the female flower is a stigma that becomes glossy when it is receptive to pollen. Pollination occurs when pollen is successfully transported to the stigma.

Pollination Assistance

• In nature, pecan trees are almost exclusively cross-pollinated. Self-pollination is indicative of inadequate levels of pollen availability during female flower receptivity, resulting in reduced yields, smaller nut size and reduced kernel percentage. Using primarily the wind to spread, pecan trees can cross-pollinate with other varieties of pecan trees up to a quarter mile away; however, spacing within 200 feet is preferred. Plant at least two cultivars of pecan trees to ensure consistently high nut yields. Ideally, you should select an equal number of protoandrous and protogynous cultivars when planting a pecan grove.

Considerations

• Flowering times may vary significantly year to year. Pecan trees consistently bloom true to the protogynous or protandrous pattern, but there can be seasonal differences in the degree of overlap and flower development timing. Trees that have significant overlap of receptivity and pollen shed one year may have total separation of the two events the next year. Age of tree, flower position and when bud break occurs will also affect flower timing. Young and old trees tend to flower at somewhat different times from one another. Flowers located lower and more interior on the tree tend to mature faster. Finally, cultivars that leaf out sooner in the spring generally follow suit with earlier flowering.