| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'I'm the Mom' | Medium | Blue/Green | Streaked | Yellow | Unknown | | | Ziarek, Ken | --NR-- |
| 'M Go Blue' | Large | Blue/Green | - | - | Hybrid | - | July into August | Schmidt, Bevie | .2009 |
| 'Maddren' | Giant | Blue/Green | - | - | Hybrid | Pale-Lavender | June into July | Gilligan, Madelon | .2012 |
| 'Made You Look' | Medium | Yellow | - | - | Hybrid | Pure-White | July | Asch, Stuart | .2000 |
| 'Madison Mine' | Large | Blue/Green | - | - | Hybrid | Pale-Lavender | July into August | Zilis, Mark & Schwarz, Jim & Schwarz, Karen | .2011 |
| 'Magnificence' | Large | Med-Green | Marginal | White | Hybrid | - | - | Livingston, Ron | --NR-- |
| 'Main Event' | Medium | Yellow | - | - | Hybrid | Near-White | June into July | Ward, Dr Dick & Ward, Jane | .2015 |
| 'Mama Bear' | Large | Light-Green | - | - | Hybrid | - | - | Schmidt, Bevie | .2009 |
| 'Man on the Moon' | - | Blue/Green | Streaked | White | TC Sport | - | - | Beilstein, Doug & Zilis, Mark | .2009 |
| 'Mañana' | Large | Dark-Green | - | - | Unknown | Near-White | - | Tompkins, Chet & Ruh, Peter & Ruh, Jean | .2001 |
| 'Mandelbrot Set' | Giant | Light-Green | - | - | Hybrid | - | June | Nyikos, Frank | .2011 |
| 'Mango Smoothie' | Medium | Yellow | - | - | Sport | Pale-Lavender | July | Fransen, Marco & Fransen, Joyce | --NR-- |
| 'Maniac' | Medium | Med-Green | Marginal | Green | Sport | Near-White | July into August | Schwarz, Jim | .2010 |
| 'Mardi Gras Parade' | Medium | Blue/Green | Streaked | Yellow | Hybrid | Near-White | July | Vaughn, Kevin | --NR-- |
| 'Marlu's Clayton' | Large | Yellow | - | - | Hybrid | Near-White | June into July | Overhiser, Martin | .2014 |
| 'Marlu's Marshall' | Large | Blue/Green | - | - | Hybrid | Near-White | June into July | Overhiser, Martin | .2014 |
| 'Marquis' | Medium | Med-Green | - | - | Hybrid | Light-Purple | July | Savory, Robert | .1982 |
| 'Marvelous' | Medium | Blue/Green | Marginal | White | Hybrid | Near-White | June into July | Goodwin, Randy | .2021 |
| 'Mary Mary' | Medium | Dark-Green | Marginal | White | Unknown | - | June into July | Schwarz, Jim | .2009 |
| 'Master Class' | Giant | Blue/Green | - | - | Hybrid | Pale-Lavender | June into July | Gilligan, Madelon | .2012 |
| 'Maumee Bay' | Large | Med-Green | Streaked | Yellow | Unknown | | | Seale, Rob | --NR-- |
| 'Maybelline' | Large | Dark-Green | | | Unknown | | | Wasitis, Chick | --NR-- |
| 'Mayflower Morning' | Large | Med-Green | Marginal | White | Nat-Sport | Pale-Lavender | July | Meyer, Bill | --NR-- |
| 'Me and My Shadow' | Medium | Blue/Green | Medial | Green | TC Sport | Near-White | July | Schwarz, Jim | .2003 |
| 'Mean Joe Green' | Medium | Blue/Green | - | - | Hybrid | Med-Lavender | July into August | Zolock, Steve & Zolock, Sarah | .2008 |
| 'Megababy' | Small | Med-Green | Streaked | Yellow | Unknown | | | Russo, Dave | --NR-- |
| 'Memorable Moments' | Large | Med-Green | Marginal | Yellow | Hybrid | Pale-Lavender | June into July | Dean, Don | .2019 |
| 'Merna's Lemon Piecrust' | Large | Yellow | - | - | Unknown | - | - | Nash, Bill | --NR-- |
| 'Michael S. Flaherty' | Large | Light-Green | - | - | Hybrid | Pale-Lavender | June into August | Chamberlain, Steve | .2014 |
| 'Michigan Sunshine' | Large | Yellow | - | - | Unknown | - | - | Benedict, Dr Ralph (Herb) | --NR-- |
| 'Michigander' | Large | Med-Green | Marginal | Yellow | Sport | Near-White | June into July | Struhar, Bill | .2018 |
| 'Midnight Dream' | Giant | Blue/Green | - | - | Unknown | - | - | Hackbarth, Robert | .2015 |
| 'Midnight Mistress' | Large | Dark-Green | Streaked | Yellow | Sport | Med-Lavender | July into August | Hackbarth, Robert | .2015 |
| 'Midsummer Night's Green' | Large | Dark-Green | - | - | Hybrid | Med-Lavender | July into August | Goodwin, Randy | .2006 |
| 'Midwest Green' | Large | Med-Green | - | - | Sport | Pale-Lavender | July | Zilis, Mark | --NR-- |
| 'Mildred's Smile' | Medium | Yellow | - | - | Hybrid | Near-White | July | Nyikos, Frank | .2007 |
| 'Minnesota Ice' | Large | Dark-Green | Marginal | White | Unknown | | | Carlson, Monty & Carlson, Julie | --NR-- |
| 'Minnesota Mushroom' | Large | Dark-Green | Marginal | White | Unknown | | | Carlson, Monty & Carlson, Julie | --NR-- |
| 'Mint Rushmore' | Giant | Blue/Green | | | Hybrid | Near-White | June into July | Carlson, Monty & Carlson, Julie | .2021 |
| 'Minute After a Rainy Sunset' | Medium | Light-Green | Streaked | Yellow | Sport | Pale-Lavender | July into August | McHugh, Ed | .2010 |
| 'Miss AmErica' (Seltz) | Large | Blue/Green | Streaked | Yellow | Unknown | | | Seltz, Traci | --NR-- |
| 'Miss Ellie Fish' | Large | Yellow | - | - | Unknown | - | - | Hackbarth, Robert | .2015 |
| 'Miss Poland' | Small | Med-Green | Streaked | Yellow | Sport | Med-Lavender | June into July | Kijanska, Poll | .2019 |
| 'Misty Gold' | Medium | Med-Green | Streaked | Yellow | Hybrid | Pale-Lavender | July | Dishon, Jim | .1996 |
| 'Monsieur Parizeau' | Giant | Blue/Green | | | Unknown | Pale-Lavender | | Bastille, Jocelyne | --NR-- |
| 'Montreal Blue Ice Storm' | Giant | Blue/Green | - | - | Hybrid | Pale-Lavender | June into July | Wade, Van | .2007 |
| 'Moon River' | Small | Blue/Green | Marginal | White | Unknown | Pale-Lavender | June into July | Lachman, Wm & Lachman, Eleanor | .1991 |
| 'Moonlight' | Large | Yellow | Marginal | White | Sport | Pale-Lavender | July into August | Banyai, Pauline | .1977 |
| 'Mossy Stone' | Large | Med-Green | - | - | Hybrid | - | - | Schulz, Ed | .2009 |
| 'Mount Daisen' | Large | Dark-Green | - | - | Hybrid | Pale-Lavender | June into July | Sugita, Hajime & Ruh, Peter & Ruh, Jean | .2005 |
| 'Mount Olympus' | Large | Med-Green | - | - | Sport | Pale-Lavender | July | Malloy, Alex | --NR-- |
| 'Mouse Madness' | Miniature | Blue/Green | Marginal | White | Sport | - | July into August | Solberg, Robert | --NR-- |
| 'My Fair Katie' | Large | Light-Green | - | - | Hybrid | - | - | Elslager, Ed | .1998 |
| 'My Laura' | Large | Med-Green | Medial | Yellow | Unknown | - | June into July | Schwarz, Jim | .2010 |
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