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