Preen Press Info Graphic

From:

Ferguson Caras LLC
989 Herrick Brook Road
Pawlet, VT 05761
802-325-3200


Backgrounder & Images


Tough Southern Weeds

45 Weed Images & Germination Notes

Weeds are opportunistic. In the south, the long growing seasons offer weeds plenty of opportunities to germinate and grow. Southern weeds run the gamut from winter annuals and perennials to summer annuals and perennials, and in between.

Most weed seeds are found in the top six inches of the soil. Those that sprout are typically found in the top two to three inches of soil or mulch, where soil temperatures are often close to the ambient air temperature.

The many micro-climates throughout the region allow for winter weeds that persist well into summer and summer weeds that persist well into winter.


Tough Southern Summer Weeds

When battling weeds it’s smart to know thine enemy. Here are some of the weeds southern gardeners find most pernicious. These notes reflect approximate timing for USDA Zone 7.
For Zone 8, timing is roughly 2 to 3 weeks earlier.
For Zone 6, timing is roughly 2 to 3 weeks later.

spurge
To Tough Southern Summer Weed Images

Spurge (Chamaesyce sp.)
- Summer Annual
- Germination occurs when soil temperatures are between 60-90°F with optimal germination occurring between 75-85° F (May-late summer)
- Germination is typically mid- to late-summer
- This is a late germinating summer annual
- Propagation is by seed and root crowns
- Plants can flower and produce seed within 5 weeks of germination
- Grows very quickly in warm conditions
- Indicator of infertile and sandy soils
- Occurs until frost.

Sida
To Tough Southern Summer Weed Images

Sida (Teaweed) (Sida sp.)
- Summer Annual
- Germination occurs when soil temps are between 65-85°F (May- late summer)
- Propagation is by seed
- Large taproot makes it difficult to pull
- Becomes woody as season progresses
- May survive winter under certain conditions
- Found in disturbed habitats
- Occurs till frost.

Erechtites hieraciifolia
To Tough Southern Summer Weed Images

American Burnweed (Fireweed) (Erechtites hieraciifolia)
- Summer Annual
- Germination occurs when soil temps are above 50°F
- Germination is typically in early March through late May.
- Propagation is by seed, wind dispersion
- Seedhead similar to that of dandelion
- This one is best dealt with post-emergence
- Flowers late spring through fall
- If left unchecked, can reach heights of 8 feet
- Found in disturbed areas, open areas and roadsides - Occurs till frost.

Digitaria
To Tough Southern Summer Weed Images

Crabgrass (Digitaria sp.)
- Summer Annual
- Germination occurs when soil temps are above 50°F
- Germination is typically early March throughout the growing season.
- Propagation is by seed
- Prolific seed producer
- Occurs till frost

Eluesine
To Tough Southern Summer Weed Images

Goosegrass (Indian Goosegrass) (Eleusine indica)
- Summer Annual
- Germination occurs when soil temps are above 60°F.
- Compared to crabgrass, goosegrass has a late germinating period
- Germination typically begins in early April and continues throughout the growing season
- Propagation is by seed
- Prolific seed producer
- Indicator of compacted soils
- Occurs till frost

Mollugo verticillata
To Tough Southern Summer Weed Images

Carpetweed (Mollugo verticillata)
- Summer Annual
- Germination begins in March and continues throughout the growing season.
- Propagation is from tiny reddish seed
- Prolific seed producer
- Disturbed sites
- Occurs till frost

Commelina diffusa
To Tough Southern Summer Weed Images

Spreading Dayflower (Commelina diffusa)
- Summer Annual
- Germination occurs in spring (March) and extends throughout growing season
- Flowers last one day hence the name
- Propagation is by seed and stem fragments
- Prefers wet areas Found along forest edges and roadsides - Occurs till frost

Conyza canadensis
To Tough Southern Summer Weed Images

Horseweed (Mare’s Tail, Horseweed Fleabane) (Conyza canadensis)
- Summer Annual
- Germination occurs when temperatures are between 65-75°F (Early May – mid June)
- Propagation is by seed
- If left unchecked can reach heights of 6 feet
- Early invader of open, sandy disturbed sites
- Occurs till frost

Ipomoea pandurata
To Tough Southern Summer Weed Images

Morningglory (Ipomea spp.)
- Summer annual
- Ooccasionally a perennial if it regenerates from a deep taproot
- Germination occurs when soil temps are between 70-85°F (May- late June)
- Propagation is by seed or regenerating taproot
- Commonly found in disturbed areas, roadsides, along fence rows
- Occurs till frost

Lespedeza
To Tough Southern Summer Weed Images

Common Lespedeza (Japanese clover) (Lespedeza striata)
- Summer annual
- Germination begins once soil temps are greater than 60°F (early April) and continues throughout the growing season
- Propagation by seed
- Indicator of infertile and sandy soils
- Found in disturbed areas, dry soils and open woods
- Best controlled with pre-emergent as it tends to get woody as season progresses, making it harder to control post-emergence.




Kyllinga
To Tough Southern Summer Weed Images

Kyllinga (Kyllinga sp.)
- Exist as both Summer Annuals and Perennials
- Germination occurs when soil temps are above 60°F, typically late April through September
- Propagation depending on species, can either be by seed or by rhizomes
- Prolific seed producer
- Indicator of wet soils
- Occurs till frost

Cynodon
To Tough Southern Summer Weed Images

Bermudagrass (Cynodon sp.)
- Warm Season Perennial
- Germination occurs when soil temps are above 60°F, typically late April through September.
- Many species and varieties exist, including some that are propagated only by vegetative means
- Propagation is by seed, rhizomes, and stolons
- Remains green till frost
- Indicator of compacted soils
- Occurs in dry to wet open habitats, full sun
- Considered one of the “worst weeds.”

Cyperus esculentus
To Tough Southern Summer Weed Images





Yellow Nutsedge (Cyperus esculentus)
- Warm Season Perennial.
- Propagation is primarily by tubers.
- Tubers germinate when soil temps remain above 40°F (late March/early April)
- Considered one of the “worst weeds”
- Tubers can remain viable for 10 years
- Tubers are the only part of the plant that overwinters
- Tubers can emerge from a depth of a foot or more
- Tubers can emerge from a depth of a foot or more
- Simply pulling these plants is not an option as all underground tubers must be extracted
- Yellow Nutsedge tends to be more cold hearty than Purple Nutsedge
- Occurs in moist to dry soil, in cultivated and disturbed sites
- Indicator of wet soils
- Occurs till frost

Cyperus rotundus
To Tough Southern Summer Weed Images


Purple Nutsedge (Cyperus rotundus)
- Warm Season Perennial.
- Propagation is primarily by rhizomes and tubers
- Germination occurs when soil temps remain above 60°F (late April/early May)
- Tubers connect together to form “chains”
- Does not over winter as well as Yellow Nutsedge
- Is considered one of the “worst weeds”
- Under ideal conditions a single tuber can produce 99 tubers in 90 days
- Most tubers are found in the top 6-8 inches. In heavy clays the rooting system may extend to a depth of 3 feet
- Occurs in moist to dry soil, in cultivated and disturbed sites
- Indicator of wet soils
- Occurs till frost

Image Coming


Doveweed (aka Naked Stem Dewflower) (Murdannia nudilora)
- Summer Annual
- Germination occurs when soil temperatures are between 60-90°F (May – late summer)
- Optimum germination occurs once soil temps reach 70°F
- This is a later germinating summer Annual
- Propagation is by seed and stem fragments
- New and emerging weed that is becoming problem across the south
- Carried by birds hence the name
- While often associated with shady moist habitats, it can be found in hot dry areas too
- Occurs until frost.

Tough Southern Winter Weeds


These notes reflect approximate/average timing for USDA Zone 7.
For Zone 8, timing is roughly 2 to 3 weeks earlier.
For Zone 6, timing is roughly 2 to 3 weeks later.

Poa annua
To Tough Southern Winter Weed Images

Annual Bluegrass (Poa annua)
- Winter Annual
- Germination occurs once soil temperatures drop below 70°F
- Germination will begin as early as September and will continue for the next 3-4 months
- Flowers throughout growing season
- Propagation is by seed
- Prolific seed producer
- Indicator of wet, high fertility, shaded and compacted soils
- Plants die with arrival of hot dry weather, late May early June

Geranium
To Tough Southern Winter Weed Images

Carolina Geranium (Geranium carolinianum)
- Winter Annual
- Germination occurs once soil temps drop below 70°F (early September)
- Propagation by seed
- Plants die with arrival of hot dry weather, late May early June

Cardamine
To Tough Southern Winter Weed Images

Hairy Bittercress (Cardamine hirsute)
- Winter Annual
- Germination occurs once soil temps drop below 70°F
- Germination will typically begin in late September and will continue through April
- Very invasive
- Propagation is by seed
- Occurs in wet disturbed areas
- Plants die with arrival of hot dry weather, late May-early June

Scleranthus annuus
To Tough Southern Winter Weed Images

Knawel Weed (Scleranthus annuus)
- Winter Annual
- Germination begins once soil temps drop below 70°F (early September)
- Propagation is by seed
- May be confused with creeping phlox
- Occurs in disturbed sites, dry and sandy soils
- Plants die with arrival of hot dry weather, late May-early June

Lamium
To Tough Southern Winter Weed Images

Henbit (Lamium amplexicaule)
- Winter Annual
- Germination begins once soil temps drop below 70°F (early September)
- Propagation is by seed
- Often confused with purple deadnettle
- Indicator of high fertility soils
- Found in disturbed sites and turf
- Plants die with hot dry weather in late May-early June

Lamium purpureum
To Tough Southern Winter Weed Images

Purple Deadnettle (Lamium purpureum)
- Winter Annual
- Germination begins once soil temps drop below 70°F (early September)
- Propagation is by seed
- Often confused with henbit
- Found in disturbed sites
- Plants die with arrival of hot dry weather, late May-early June

Stellaria media
To Tough Southern Winter Weed Images


Common Chickweed (Stellaria media)
- Winter Annual
- Germination occurs when soil temps are between 50 -70°F
- Germination usually begins in September and, depending on weather, through spring into April
- Propagation is by seed
- Can complete life cycle in 5-6 weeks
- Has capacity to produce thousands of seeds, per plant per season
- Seeds remain viable in the soil for many years
- Seed germination decreases with increased depth, therefore turning the soil to bury chickweed seed is an option but, in the process, other weeds’ seeds will be brought to surface to germinate
- Occurs in open disturbed areas
- Indicator of compacted soils
- Plants die with arrival of hot dry weather, late May-early June

Galium aparine
To Tough Southern Winter Weed Images

Catchweed Bedstraw (Stickywilly, Cleavers) (Galium aparine)
- Winter Annual
- Mat-forming
- Propagation is by seed
- Seed will not germinate if left on top of the soil due to high light intensity
- Seed can germinate when buried up to 3” deep
- Seeds are viable in the soil for up to 3 years
- Plant easily breaks apart for seed dispersion, attaches to animals’ fur or peoples’ clothes or hair
- Found in moist shady disturbed areas
- Plants die with arrival of hot dry weather, late May early June

Cerastium glomeratum
To Tough Southern Winter Weed Images

Sticky Chickweed (Cerastium glomeratum)
- Winter Annual
- Germination occurs when soil temps are between 50-70°F
- Germination usually begins in September and depending on weather through spring into April
- Propagation is by seed
- Can complete lifecycle in 5-6 weeks
- Seeds remain viable in the soil for many years
- Seed germination decreases with increased seeding depth
- Turning the soil to bury chickweed seed is an option, but in the process other weeds seeds will be brought to the top
- Plants die with arrival of hot dry weather, late May early June

Glechoma hederacea
To Tough Southern Winter Weed Images

Ground Ivy (Glechoma hederacea)
- Cool Season Perennial
- Germination begins once soil temps drop below 70°F
- Germination usually occurs in early September
- Propagation is by seed and creeping stems/stolons
- Common in shade
- Introduced as a shade tolerant ground cover
- Often confused with common mallow
- Has square stems and a minty-scent when crushed
- Indicator of wet shady soils
- Poisonous if ingested
- Tends to remain vegetative throughout summer under certain conditions

Modiola caroliniana
To Tough Southern Winter Weed Images

Bristly Mallow (Modiola caroliniana)
- Cool Season Perennial
- Germination begins once soil temps drop below 70°F
- Germination usually occurs in early September
- Propagation is by seed
- Confused with ground ivy, aka creeping Charlie
- Occurs in disturbed habitats with moist to dry soils
- Has round stems

Allium vineale
To Tough Southern Winter Weed Images

Wild Garlic (Allium vineale)
- Cool Season Perennial
- Germination usually occurs once soil temps reach 60°F
- Germination usually late September/October)
- Propagation is by seed, aerial bulbils and underground bulblets
- Wild garlic has a hollow stem (unlike wild onion)
- Plants die with arrival of hot dry weather, late May-early June

Hypochoeris radicata
To Tough Southern Winter Weed Images

Common Cat’s-ear Dandelion (Hypochoeris radicata)
- Cool Season Perennial
- Germination occurs in fall (September) once soil temperatures drop below 70°F.
- Flowers primarily late spring into early summer
- A dandelion seed head can produce between 100 to 300 seeds
- Occurs in disturbed sites, pastures, fields
- Seen throughout summer in many areas
- Tends to remain vegetative throughout summer under certain environmental conditions

Latuca canadensis
To Tough Southern Winter Weed Images

Tall Lettuce (Latuca canadensis)
- Cool Season Biennial
- Germination occurs in the fall once soil temperatures are below 70°F
- Germinaton usually early September)
- Propagation is by seed
- Forms large tap root in first year
- Early invader of disturbed areas, pastures and road sides

Vicia
To Tough Southern Winter Weed Images

Narrowleaf Vetch (Vicia sativa) & (Vicia sp.)
- Cool Season Annual
- Germination occurs once soil temps drop below 70°F
- Germination usually early September and continues throughout the growing season.
- Propagation is by seed
- Found in disturbed areas
- Plants die with arrival of hot dry weather, late May-early June.




Image coming

Annual Blue-eyed grass (Sisyrinchium rosulatum)
- Winter Annual
- Germination occurs in fall (September) and extends throughout growing season.
- Propagation by seed
- Not truly a grass (Iris family)
- New and emerging problem weed across the south
- Similar in appearance to goosegrass, but with winter weed timing
- Plants die with arrival of hot dry weather, late May early June

Weed Control Notes

  • To rid garden/landscape beds of already growing annual weeds and tough perennial weeds: pull or dig them out, getting as much of the underground support system as possible. Foliar sprays such as Roundup kill weed top-growth and roots. Most organic options kill top-growth only, and not the roots.
  • To stop new weeds from growing, prevent the seeds from germinating by applying a combination of mulch & pre-emergent. Mulch deprives seeds of the light they need to sprout. Pre-emergents prevent seeds from forming roots, so they never grow. Cover flower and landscape beds with a 3-inch layer of mulch topped by a long-lasting pre-emergent such as Preen Southern Weed Preventer (stops weeds up to four months) or Preen Organic Vegetable Garden Weed Preventer (stops weeds for up to four weeks).
    - Apply in spring to stop late-germinating winter weeds and summer weeds
    - Apply in late summer or fall to stop late germinating summer weeds and new winter weeds.
  • Another solution is to use Preen Mulch Plus, a bagged shredded-wood mulch with two pre-emergent weed preventers mixed in. A 2-inch layer of this mulch stops weeds up to six months (regional natural mulch mixes packaged at 49 locations coast-to-coast, sold nationwide at Lowe's and independent garden centers).

-30-

Download Word Version of Backgrounder
To the Image Gallery

All images are made available for editorial and educational uses by Preen.com and by special arrangement with Richard Old of XID Services. Please note the credit embedded in each image. XID images come from the interactive DVD: 1200 Weeds of the 48 States and Adjacent Canada (http://xidservices.com/order).