Half of the year is already over and there are fewer and fewer plants still flowering outside. Instead, the intensive harvest time begins, for example for plums, early apples and most cereals. The fruit ripening of rowan trees heralds the beginning of late summer. At this time of the year we are dealing with the two very similar, introduced goldenrod species *Solidago canadensis* and *Solidago gigantea*. Please make a Flora Incognita or Flora Capture observation as soon as you see one of the two species in bloom!
The phenological clock is ticking...
The [Canadian goldenrod](#/species-detail/347) originates from North America and is one of the few species that does not start flowering until late summer. Its stem is hairy and green, the leaves are rough on the top and slightly arched between the nerves. Young flower shoots are overhanging. The ray florets (the elongated petals on the outside of the capitula) are relatively short and often rolled up.
The [Early goldenrod](#/species-detail/1470) differs from the Canadian goldenrod by a bare, often reddish or greyish stem. The leaves are smooth and the ray florets relatively long and not rolled. Both goldenrod species reproduce rapidly over underground rhizomes and spread particularly along railway tracks and on fallow land. With up to 19,000 seeds per plant, the golden rods also easily escape our gardens and often displace native species through their mass populations.