Weeds usually cause problems when gardening, but did you know weeds can also act as soil indicators, informing you of what type of soil you have in the garden?
Weeds as Soil Indicators
Acid soil: Ox-eye daisy (Chrysanthemum leucanthemum), curly dock (Rumex crispus), sheep sorrel (Rumex acetosella), sow thistle (Sonchus species), prostrate knotweed (Poly-gonum aviculare), lady’s-thumb (Polygonum persicaria), wild strawberries (Fragaria species), plantain (Plantago major), rough cinquefoil (Potentilla monspeliensis), silvery cinquefoil (Potentilla argentea), hawkweeds (Hieracium aurantiacum and pratense), knapweeds (Centaurea species).
Alkaline soil: Field peppergrass (Lepidium virginicum), goosefoot (Chenopodium species), gromwell (Lithospermum officinale), true chamomile (Anthemis nobilis), bladder campion (Silene latifolia).
Wet soil: Cattail (Typha latifolia), horsetail (Equisetum arvense), bull sedge (Carex lasiocarpa), lady’s-thumb (Polygonum persicaria), joe-pye weed (Eupatorium purpureum), silvery cinquefoil (Potentilla argentea), curly dock (Rumex crispus), mosses, Pennsylvania smartweed (Polygonum pensylvanicum), tall buttercup (Ranunculus acris), creeping buttercup (Ranunculus repens). May apple (Podophyllum peltatum), sheep sorrel (Rumex acetosella), thyme-leafed speedwell (Veronica serpyllifolia), Canada goldenrod (Solidago canadensis), lance-leaved goldenrod (Solidago graminifolia), meadow pink (Lychnis floscuculi), jewelweed (Impatiens pallida), coltsfoot (Tussilago farfara), marsh mallow (Althaea officinalis), sweet flag (Acorus calamus), ground nut (Apios americana).
Dry soil: Virginia pepperweed (Lepidium virginicum), rough cinquefoil (Potentilla monspeliensis), potato vine (Ipomoea pandurata).
Sandy soil: Sandbur (Cenchrus species), dog fennel (Eupatorium capillifolium), cornflower (Centaurea cyanus), yellow toadflax (Linaria vulgaris), small nettle (Urtica urens), arrow-leafed wild lettuce (Lactuca pulchella), maltese thistle (Centaurea melitensis).
Heavy soil: Wild garlic (Allium vineale), dandelion (Taraxacum officinale), broadleaf dock (Rumex obtusifolius), creeping buttercup (Ranunculus repens), plantain (Plantago major).
Poor soil with low humus: Sheep sorrel (Rumex acetosella), dog fennel (Eupatorium capillifolium), broom sedge (Andropogon virginicus), yellow toadflax (Linaria vulgaris).
Soil with a hardpan or hard crust: Horse nettle (Solanum carolinense), pennycress (Thiaspi arvense), quack grass (Agropyron repens), field mustard (Brassica nigra), morning-glory (Ipomoea purpurea), pineapple weed (Matricaria sauveolens).
Previously cultivated soil: Lamb’s-quarters (Chenopodium album), plantain (several species), ragweed (Ambrosia artemisiifolia), purslane (Portulaca oleracea), dandelion (Taraxacum officinale), chickweed (Stellaria media), rough pigweed (family Amaranth), carpetweed (Mollugo verticillata).
Rich soil: Chicory (Cichorium intybus), pigweeds (family Amaranth), purslane (Portulaca oleracea), dandelion (Taraxacum officinale), lamb’s-quarters (Chenopodium album), burdock (Arctium minus), pokeweed (Phytolacca americana), butter print (Abutilon theophrasti), Queen Anne’s lace (Daucus carota).