How do I identify smooth crabgrass?

Smooth crabgrass (Digitaria ischaemum) has smooth, flattened leaf sheaths and blades, and forms a low-growing, spreading habit. Its seed heads are typically digitate (finger-like) with slender green or purplish branches.

When does smooth crabgrass germinate?

Smooth crabgrass typically germinates in late spring or early summer when soil temperatures consistently reach 10-13°C (50-55°F).

What conditions favor smooth crabgrass growth?

This weed thrives in warm weather, full sun, and disturbed or compacted soils. It is often found in lawns with thin or unhealthy turf.

How can I prevent smooth crabgrass from growing in my lawn?

Pre-emergent herbicides applied in early spring before germination can effectively control smooth crabgrass. Maintaining a healthy, dense lawn through proper mowing, watering, and fertilization also helps prevent its establishment.

How can I control existing smooth crabgrass?

Post-emergent herbicides can control actively growing smooth crabgrass. Hand-pulling young plants can be effective if done before they set seed. Improving lawn health is crucial for long-term control.

Crab Grass (Digitaria ischaemum) – Care, Benefits & Growing Guide

Smooth Crabgrass Toxicity

Safety information from plant toxicity data

Toxicity details for Smooth Crabgrass
Attribute	Value
Toxic for humans	No 0/5 intensity
Toxic for pets	No 0/5 intensity
Edible	No

None

Smooth Crabgrass Quick Facts

Key traits and growing stats from plant data

Plant Type: Grass
Plant Category: Ornamental
Plant Place Type: Garden
Lifespan: Annual
Plant Height: 0.1-0.3 m
Spread: 0.3-0.6 m
Tall Or Wide: Wide
Growth Rate: Fast
Dormancy: None
Leaf Color: Green
Leaf Type: Simple
Optimal Sunlight (lux): 60000
Weed Status: Yes

Care guide for Smooth Crabgrass

Watering, pruning, propagation, and repotting details from plant data

Water

Water moderately during active growth, allowing the soil to dry slightly between waterings. Reduce watering in cooler months. Ensure good drainage to prevent waterlogged conditions, which can lead to root rot.

Pruning

Pruning is generally not required for Digitaria ischaemum as it is an annual weed. If managing its spread, mowing or removal before seed set is the primary method.

Propagation

Digitaria ischaemum primarily propagates through seeds. Seeds are wind-dispersed and can remain viable in the soil for extended periods, allowing for germination in subsequent growing seasons.

Repotting

Repotting is not applicable to Digitaria ischaemum, as it is an annual weed typically found in lawns and disturbed soils. It does not require container culture.

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Flowering & Fruiting Cycles

Monthly activity intensity for bloom and fruit across both hemispheres.

Northern hemisphere

Flowering & fruiting calendar

Peak bloom · MarPeak fruit · Jan

FloweringFruiting

Southern hemisphere

Flowering & fruiting calendar

Peak bloom · AugPeak fruit · Feb

FloweringFruiting

Image Gallery

Photos of Smooth Crabgrass (Digitaria ischaemum)

Smooth Crabgrass Names & Synonyms

Common names and botanical synonyms

Common Names

Crab Grass
Red Millet
Small Crabgrass
Smooth Crab Grass
Smooth Crabgrass
Smooth Finger-Grass
Smooth Fingergrass
Smooth Summer Grass
Smooth Summergrass

Synonyms

Digitaria asiatica Tzvelev
Digitaria glabra (Schrad.) P.Beauv.
Digitaria humifusa Pers.
Digitaria paspaliformis J.Woods
Panicum elegans Heuff.
Panicum humifusum (Pers.) Kunth
Panicum ischaemum Schreb.
Paspalum humifusum (Pers.) Poir.
Sanguinaria humifusa (Pers.) Bubani
Syntherisma glabra Schrad.
Syntherisma humifusa (Pers.) Rydb.
Syntherisma ischaemum (Schreb.) Nash

Smooth Crabgrass Taxonomy

Botanical classification

Taxonomic classification of Smooth Crabgrass
Rank	Name
Kingdom	Plantae
Division	Tracheophyta
Class	Liliopsida
Order	Poales
Family	Poaceae
Genus	Digitaria
Species	Digitaria ischaemum

Similar Plants

Similar in genus Digitaria

Hairy Crabgrass

Digitaria sanguinalis

Asian Crabgrass

Digitaria bicornis

Fall Witchgrass

Digitaria cognata

White Fonio

Digitaria exilis

Smooth Crabgrass FAQs

Answers based on plant encyclopedia data

How do I identify smooth crabgrass?
Smooth crabgrass (Digitaria ischaemum) has smooth, flattened leaf sheaths and blades, and forms a low-growing, spreading habit. Its seed heads are typically digitate (finger-like) with slender green or purplish branches.
When does smooth crabgrass germinate?
Smooth crabgrass typically germinates in late spring or early summer when soil temperatures consistently reach 10-13°C (50-55°F).
What conditions favor smooth crabgrass growth?
This weed thrives in warm weather, full sun, and disturbed or compacted soils. It is often found in lawns with thin or unhealthy turf.
How can I prevent smooth crabgrass from growing in my lawn?
Pre-emergent herbicides applied in early spring before germination can effectively control smooth crabgrass. Maintaining a healthy, dense lawn through proper mowing, watering, and fertilization also helps prevent its establishment.
How can I control existing smooth crabgrass?
Post-emergent herbicides can control actively growing smooth crabgrass. Hand-pulling young plants can be effective if done before they set seed. Improving lawn health is crucial for long-term control.

Smooth CrabgrassDigitaria ischaemum

Smooth Crabgrass Care Summary