Smartweed has its day

Bob Dluzen
Special to The Detroit News

We know all too well weeds appear every year even in the most well tended gardens. However, they are not always present in the same proportion from one year to the next.

For example, one year you may see a severe outbreak of pigweed while other species would be growing in more modest numbers.

Generally, this is weather related although other factors come into play. Drought years will encourage dry-loving plants while seasons with abundant rain will allow moisture-loving species to thrive.

I have a relatively large garden area that I purposely left fallow this year, partly because of time constraints. I tilled it once during the dry weeks in March to destroy early emerging weeds and those that came up last fall and overwintered.

Several weeks later as more weeds appeared and made more growth, I tilled under the second wave of weeds while they were still succulent and before they produced seeds.

Now, in late August, that area has an almost pure stand of smartweed growing -- caused by a combination of weather, soil conditions and tillage.

That spot is low and is always one of  the last spots to dry out in the spring. It is land-locked having nowhere for excess water to drain to other than into the soil profile.

It just so happens that smartweed is happiest growing in wet, poorly drained soil conditions, even though we’ll see it in small numbers every year.

All of the rain we’ve had this year has kept that area from drying out to the extent it would normally.

The small smartweed flowers are an attractive shade of pink.

Smartweed also tends to grow best in highly fertile soil. My last soil test about four years ago showed that area to be somewhat low in phosphorus at that time.

I’m sure the results of a new test would be much higher since I’ve had that spot under an intensive soil building regime of cover crops and plow-down crops.

Timing is important for seed germination. Since those two earlier tillings knocked back most of the weeds that would otherwise have established themselves and been competitors, it left an opening for smartweed to take over.

Additionally, smartweed seeds will not germinate if they are not exposed to light, even a brief flash of light will break seed dormancy. Tuning over the soil during tilling provided the needed light.

So three critical events came together in the right order to cause this interesting phenomenon.

Will this pure stand of smartweed cause extra problems in the future? Could be, since each smartweed plant can potentially produce 20,000 seeds.

Not all of those seeds will germinate. A large number will be eaten by ground-dwelling beetles and crickets -- others will succumb to soil fungus or bacteria.

I’ll let the smartweed be for a little while just for the novelty of seeing all of those little pink flowers.

The seeds are edible for birds. I haven’t seen any birds feeding on them yet but will keep a close eye on the plants. If the birds like them, I’ll just keep them growing and let the birds have their fill.