During my monthly meeting of the South Carolina Herbal Society this week, we learned that “weeds” can tell us something about our soil structure. Most of these plants are actually wildflowers or herbs. Basically, what we call weeds are nothing more than wild plants. Plants are intelligent and have an underground communication system. They know where it’s best for them to grow. So, if we listen to them, we will know better what to plant in that soil or how to amend the soil to plant what we want.
SOGGY SOIL WEEDS
If you see any of these weeds growing, you most likely have soggy soil:
- Yellow Dock
- Foxtail grass
- Joe Pye Weed
- Poison Hemlock (looks similar to Queen Anne’s Lace but has smooth stems compared to Queen Anne Lace’s hairy stems)
- Oxeye daisy
These plants naturally grow in wetlands or soil that doesn’t drain well. There’s not much you can do to amend soggy soil if your land tends to drain in that direction, but this soil is great for many beautiful plants. These plants also love soggy soil:
- Pussy willow
- Curly willow
- Japanese iris
- Siberian iris
- Yellow flag
- Cardinal flower
- Pitcher plants
COMPACTED OR CRUSTY SOIL WEEDS
This type of soil occurs when the land has been left fallow for a while or when the soil has been worked when wet. You would find these types of weeds growing in compacted or crusty soil:
- Chicory weed
- Wild mustard
Wild mustard is a member of the brassica family, and all brassicas will grow well in this type of soil.
To amend the soil for planting other crops, you can plant rye grass or clover to break up the compaction. Also, adding lots of organic matter (compost) will help.
Finally, never work the soil when it’s wet. It will ruin the soil structure.
ACIDIC SOIL WEEDS
If you see these weeds in your yard (or an area of your yard), then they’re telling you the soil has a pH less than 7.0 (acidic):
- Wood sorrel
- Stinging Nettle
There are quite a few acid-loving plants that you can cultivate. The following plants can often tolerate a pH as low as 5.0:
If your soil is very acidic, you can neutralize the pH by adding dolomitic limestone. Wood ashes can also raise the pH; apply 25 lb per 1000 square feet every two to three years.
Overall, compost is a better buffer to raise your soil’s pH to 6.5 to 6.8, a range perfect for most garden plants.
ALKALINE SOIL WEEDS
Known as “sweet weeds,” these weeds will grow where the soil has a pH greater than 7.0 (alkaline):
- Pepper grass
- Nodding Thistle
There are quite a few cultivated plants that will grow well in this type of soil:
- Salad burnet
- Scarlet pimpernel
- Persian candytuft
- Baby’s breath
- Mountain pinks
Once again, compost is a great neutralizer and can be used to amend alkaline soil, too.
WORN OUT SOIL WEEDS
Where soil has poor fertility or is “worn out,” you’ll find the following weeds growing well:
- Wild wormwood
- Mugwort (Artemisia)
- Wild carrot
- Wild parsnip
- Wild radish
Plants that grow in poor soil usually don’t need a lot of water either.
If you have this type of soil, all is not lost. The following plants can be cultivated in poor soil and still grow:
- Butterfly weed
To amend poor soil, apply organic fertilizer. Adding compost to the soil will also help.
RICH SOIL WEEDS
If you have fertile soil, you will find these weeds, or “spring tonic herbs,” growing:
- Lamb’s quarter
The following plants will give you a little better indication of the richness of the soil:
- Redroot pigweed – grows in areas with high Nitrogen
- Knapweed and Red clover – grow in areas with excessive Potassium
- Purslane and Mustard – grow in areas rich in Phosphorus
Rich soil is perfect for heavy feeders such as:
Although only an actual soil test can give you detailed information about your soil, the wild plants we see willingly growing in our yards can still give us an idea of what’s going on in that dirt of ours. Those “weeds” may not speak loudly, but we can still hear them if we’re willing to listen.
What weeds are speaking in your yard?