This is a fast-growing tree that averages about 36 inches of growth per year. I have to constantly sweep them off my porches and my driveway is a mess! The seeds are the largest of all birches native to the U.S. Q: My river birch tree has dropped long worm-like seeds, then whirlybird things. I have several river birch trees planted near each other. The male flowers (catkins) form in summer and overwinter. A healthy River Birch can live up to 50 years. Seed dormancy: River birch seeds are non-dormant if germinated under long days (light for >16 hours). It does point to conditions the trees experienced in the last year or so. Thank you for the question. Most will reach a Minimum of 20 years. Heavy seed production occurs almost every year. I've tried to research what the problem might be, but there seem to be a number of potential reasons. They grow very quickly so … Each year about this time they start dropping leaves and this continues until fall. It looks like it's snowing. Now it's dropping small yellow-like things for 3 weeks now. The leaves make a mess of the yard all summer. River birch seeds. Dwarf varieties may grow a bit slower, taking 10 years or so to reach 10 feet. Seeds are shed in late spring and early summer. In order to germinate in the dark, seeds need to be stratified for 60 days. The river birch is a popular tree for river banks and wet parts of the garden. Plant a river birch tree in spring or fall when the soil is moist and the temperatures are cool. There are many factors to the longevity of your birch, which you can find on just about any garden site. Learn more river birch tree facts and how to use them in the landscape of your home right here. River birch trees bear male and female flowers on the same plant. The numerous winged seeds mature in late spring (unlike all other birches which produce seed in the fall), packed between the bracts of the female catkins. As the tree gets older, the red bark will darken and eventually turn grey. Has nothing to do with the coming winter, for example. River birches are not particularly long-lived trees, however. In spring female flowers emerge, the catkins elongate and pollination takes place. It’s not a predictor, if that’s what you’re wondering. Its attractive bark is especially striking in the winter when the rest of the tree is bare. Every seed will germinate and they are easy to grow. The Betula pendula produces millions of seeds from each tree every year.