When most people think of spring flowers their minds envision tulips, crocus, daffodils and hyacinths. But these are late bloomers when compared to the real first flowers of spring. Since April 15, the earliest record I have of any spring flowers, I have anticipated the first flowers of spring. But cold weather and snow have delayed their opening a bit. I start looking for the first blooms of spring in swamps and marshes while the snow still covers the icy ground. What I am looking for many people overlook and do not even consider flowers.
Yesterday, the air temperatures finally got above 50 degrees. The snow is still deep and the ground still frozen but life is awakening in the swamps. There are mallard ducks, Canada geese, sandhill cranes, and blue herons arriving to begin again the cycle of life. And flowers are blooming, too. So far it is only tag alder (Alnus incana, Family Betulaceae, the birches) but it is abundantly flowering.
Tag alder is a sprawling shrub with black bark marked by small light-colored horizontal lenticels giving it a speckled appearance (its other name is speckled alder). The range of tag alder is circumboreal and it occurs from eastern Canada west to Alaska and south into the northern tier of the United States and at high elevations further south and across Siberia to northern Europe. It grows in wet soils that may be groundwater fed or have lateral subterranean water movement. Tag alder is often found along lake shores, river and creek banks, and in forested swamps. Tag alder can also form plant communities where it is the primary woody plant species. These are variously called alder thickets, alder swamps, or alder wooded fens.
Tag alder blooms very early before the leaf buds have opened. Flowers are borne in spike-like inflorescences (or aments) of either pistillate or staminate flowers that lack petals. The staminate ament which is a one to two-inch drooping catkin is the most obvious flower on the alder. The pistillate ament is smaller looking more like a small purple cone. Over the next several days thousands of these flowers will bloom and the pollen grains from the staminate aments will be shed by the millions. Some will land on the pistillate aments and make contact with the stigmas and start the process of fertilization and seed development. The staminate aments wither and fall after pollen has been shed.
After pollination the leaves begin to emerge and enlarge. Leaves of tag alder are ovate to elliptical in outline, the tip somewhat pointed to blunt, dark green and rough surfaced above and whitish-green below. The leaf margins are both coarsely and finely serrate. The base of the leaf blade is slightly asymmetrical.
Later in the summer aments for the next spring season begin to develop. The staminate aments, which are full of protein rich pollen, are eaten by ruffed grouse in the winter.
As the season progress the pistillate ament will grow larger to about a half-inch in size. It will at first look like a green cone, although it is not a true cone like in pines. By autumn the winged seeds will have matured. At that time the green pistillate aments will become dry, brown and woody and then open exposing the winged seeds to the wind. Not all of the seeds are blown away and many remain inside the aments throughout the winter where they become an important food for chickadees and other small birds.
Tag alder is capable of fixing atmospheric nitrogen. It does so through a symbiotic relationship with Frankia alni, an actinomycete (filamentous bacteria) that forms lumpy nodules on its roots. The symbiotic relationship tag alder has with Frankia alni enriches the soil making it possible for many other species of plants to grow in the alder thickets. Tag alder swamps are typically rich in plant species. Species frequently found in alder swamps are crested fern (Dryopteris cristata), spinulose woodfern (Dryopteris carthusiana), dewberry (Rubus pubescens), marsh marigold (Caltha palustris), avens (Geum macrophyllum), sedges (Carex trisperma, C. stricta, C. intumescens), white violet (Viola pallens), marsh blue violet (Viola cucullata), red currant (Ribes triste), skunk currant (Ribes glandulosum), black currant (Ribes americanum) and many others.
Tag alder is an important woody shrub in wetlands. Its seeds and staminate aments are winter food for songbirds and ruffed grouse. The shrubs form thickets which provide shelter in the winter. In the summer the network of branches in alder thickets are used as nesting sites by a variety of songbirds especially warblers. As one of the few wetland plants that can fix atmospheric nitrogen it enriches the soil where it grows making it possible for other species to thrive.