Show #130 - March Lawn Care: Winning the War on Winter Weeds

March signals the true beginning of spring — and the explosive arrival of the winter weed family. Even before snow fully melts, more than 160 leafy broadleaf weeds are already germinating. This episode of Great Gardens Radio explains how to stop them now, avoid common spring mistakes, and set lawns and plants up for long-term success.

Understanding the Winter Weed Explosion

Winter weeds are all leafy weeds, not grassy ones. Every weed you see from now through early June falls into this category.

Key facts:

• Over 160 winter broadleaf weeds
• Many reproduce as both annuals and perennials
• Roots form early, foliage explodes later

Stopping them requires prevention, elimination, and soil correction — all working together.

The Three-Step Winter Weed Strategy

1. Prevent Germination

Gallery is the only product on the market that prevents all 160 broadleaf winter weeds for 8–9 months.

If you didn’t apply Gallery last fall, now is the time.

Important reminder:

• Gallery goes on top of mulch, not underneath
• Apply with a handheld spreader
• Focus on mulch beds and lawn edges (80% of weeds live here)

2. Kill What’s Already Growing

Fertilome’s Weed Free Zone eliminates existing leafy weeds without harming grass. Every weed you see now should be killed before it sets seed.

3. Change the Environment Weeds Love

Weeds prefer acidic soil (pH 4.5). Lawns thrive in alkaline soil (pH 6.5).

That difference represents 200 points on the pH scale.

Actions to take now:

• Lime if you haven’t in one year
• Fertilize ASAP to boost root growth
• Create conditions weeds hate

Feed Plants After a Tough Winter

Now is the best time to fertilize:

• Trees
• Shrubs
• Evergreens
• Perennials

Use products like Plant Trust or Fertilome’s Start-n-Grow to rebuild strength after winter stress.

Immediately mulch afterward to protect roots and lock in nutrients.

Warning: Ignore March Crabgrass Ads

You’ll hear dozens of ads pushing crabgrass preventers in March — ignore them.

Why:

• Box-store crabgrass preventers last only 10 weeks
• Applied too early, they fail before crabgrass germinates

When and How to Prevent Crabgrass Properly

Dimension Is the Gold Standard

• One application lasts all season
• Non-toxic and non-staining
• Does not root prune
• Affordable

Best timing:

• April 15 is ideal
• Any time during April works

Two Important Exceptions

Stiltgrass in heavy shade

• Apply Dimension by March 20
• Loves shade, moisture, and low areas
• Existing stiltgrass can be selectively killed

Seeding a sunny lawn in spring

• Apply Tenacity granular April 15–20
• Seed lawn
• After mowing once or twice, apply Dimension
• This two-step approach is the only solution

March Lawn Health Indicator

March reveals lawn strength:

• First lawn to green up = strongest
• Last lawn to green up = weakest

This visual cue tells you where soil improvement, fertilization, and overseeding are needed.

Cold-Damaged Plants: What to Do Now

After winter damage:

• Trim off dead or damaged foliage
• Fertilize immediately

Now is the best trimming window of the year for:

• Evergreens
• Roses
• Summer bloomers

Old gardening rule:

The harder the winter, the harder the spring trim.

Do not trim spring bloomers until after flowering.

Sunny vs. Shady Lawn Seeding

Sunny and shady lawns behave completely opposite.

Sunny Lawns

• Spring seeding not recommended
• Seeds won’t germinate until nights stay above 45°
• Root growth is lost once top growth begins

Shady Lawns

• Germinate twice as fast
• Can be seeded beginning in March
• Thrive without summer leaf drop stress

Critical warning:

• Never apply crabgrass preventer in shade
• Crabgrass does not grow in shade

Why Shade Seed Quality Matters

Shade seed blends should include:

• Chewings fescue
• Fine or hard fescue
• Perennial rye
• Minimal bluegrass

Quality standards:

• 99% pure seed
• Not 48% filler like box stores
• Smaller seed size
• Higher performance

Shade seed costs more — because it works.

Understanding Sun Exposure Correctly

In gardening, sun only counts 11 a.m. to 5 p.m.
That’s when you’d get a suntan — and when plants truly receive usable light.

Categories:

• Light shade: 3 of 6 hours
• Medium shade: 2 of 6 hours
• Dense shade: 1 of 6 hours

Sun exposure can change in a single step across a yard, requiring different grass seed or plants.

Why Plant Placement Matters

Needle evergreens demand sun:

• Juniper
• Arborvitae
• Pine
• Spruce
• Cypress

Many leaf plants tolerate both sun and shade.

Correct placement maximizes performance — which is why landscape design matters.