Wildflowers may not be what they seem to be. California poppy, various lupines, various sages and several others are native species. Saint John’s wort, periwinkle, mustard and several others are not native. They are exotic but naturalized, so can proliferate as if they are native. In other words, several of the most familiar of wildflowers are invasive weeds.
In fact, some of the most invasive weeds were once more popular for their pretty flowers. These includes Saint John’s wort and periwinkle. Pampas grass, various brooms, yellow flag iris and Hottentot fig are more examples. Mustard likely originated as a home garden vegetable. Many grassy weeds were livestock fodder. Not many weeds were accidental.
Nonetheless, invasive weeds are here and established within local ecosystems now. By their simplest definition, weeds are merely unwanted vegetation. Native brambles qualify as invasive weeds as they invade home gardens. Because they are native, though, they are not invasive in the wild. Most of the most aggressive weeds just happen to be exotic.
Many invasive weeds have unfair advantages
Invasive weeds become invasive because of their various unfair advantages. Many lack pathogens that limit their proliferation wherever they are native to. Many lack competition from vegetation that they shared their natural ecosystems with. A few may actually prefer local climate to their natural climates. Weeds exhibit too much variety for generalization.
Although, generally, invasive weeds are accelerating their growth with warming weather. Most are proficient at growing faster than their competition and other preferable species. Several bloom and disperse seed before some deciduous species foliate. Weeds exploit resources before desirable species can. Several rampantly overwhelm their competition.
This is therefore a convenient time for weeding, before invasive weeds grow much more. Their roots will disperse more and be more difficult to pull from drier soil later. With more time, most weeds disperse more seed for subsequent generations. Diligence now might not eliminate all weeds for very long, but it helps. Later, weeds should be less abundant.
Highlight: Red Flowering Currant
Its natural range extends from coastal Santa Barbara County to central British Columbia. Yet, red flowering currant, Ribes sanguineum, is elusive in the wild. It is more commonly observable within relaxed landscapes of native species. Individual specimens might not perform for more than a decade but can disperse seed. It behaves as if it is growing wild.
Mature specimens of red flowering currant can grow ten feet high and half as wide. Most stay lower. It is an understory species, so it tolerates a bit of shade. It may prefer shade to warm exposures. Young specimens may be wobbly enough to justify temporary staking. Removal of deteriorating old stems promotes more vigorous growth on fresh new stems.
Pendulous conical trusses of small pink flowers bloom by late winter or very early spring. Before anyone notices, birds are likely to take the few small currants that might develop. Small palmate leaves resemble those of scented geranium, and are somewhat aromatic. They turn yellow as they shed for autumn. Red flowering currant has a foresty character. It suits casual landscapes which border or merge into undeveloped areas.
