Few notice oak blossom. The fact is that this tree has small, nondescript, greenish flowers that are difficult to see among the green foliage. You have to look very closely to see them.
Male and female oak flowers
Oak has 2 types of flowers: male, containing only stamens, and female, consisting only of a bare pistil. Male flowers gather in peculiar inflorescences, hanging from the branches like earrings. They are somewhat similar to the fringe of a carpet, only not solid, but intermittent, with small gaps. 2 or 3 female flowers each sit on special short stems. They resemble greenish grains with a red top, slightly larger than the head of a pin. It is from the female flowers that acorns then grow.
The oak begins to bloom in late spring. At this time, small, yellowish-green leaves are just beginning to bloom. Earrings also appear with them, however, due to the same color, they merge with the foliage. In the flowers forming the earring, pollen ripens, which subsequently spills out and is carried by the wind. Earrings soon dry up and fall to the ground, as their biological function ends there.
It is even more difficult to see single female flowers. Perhaps the easiest to spot is their short, bright red antennae, which serve to pick up wind-blown pollen. Closer to autumn, a tiny green flower turns into a large oval acorn. Below it is surrounded by a cup-cup, which after its fall remains on the tree for some time.
Falling to the ground in late autumn, acorns hibernate under a layer of snow that protects them from frost and helps to maintain moisture. In the spring they sprout, giving birth to young oak trees. With artificial cultivation of oaks, acorns are sown in spring. To preserve the seed, acorns are either buried in specially prepared pits for the winter, or stored in tightly closed baskets, which are lowered to the bottom of the river. The thing is that acorns are very moody and need to retain moisture and heat. Plus, they're one of the favorite treats for mice. Moreover, they are subject to decay. So it takes a lot of ingenuity to grow oak trees.
Oaks growing naturally in central Russia do not bear fruit every year, but only once every 4-7 years. The thing is that the fruiting process requires a lot of energy from the tree. After all, large and heavy acorns need a large amount of nutrients. So the tree simply does not have enough strength to bear fruit annually.