| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'M Go Blue' | Large | Blue/Green | - | - | Hybrid | - | July into August | Schmidt, Bevie | .2009 |
| 'Ma Breeder' | Large | Yellow | Streaked | Speckles | Hybrid | Near-White | June into July | Kuenster, Rod | .2008 |
| 'Macho' | Medium | Dark-Green | - | - | Unknown | Deep-Purple | August | Livingston, Ron | --NR-- |
| 'Magic Colors' | Small | Med-Green | Streaked | White | Hybrid | Light-Purple | July | Beilstein, Doug & Malloy, Alex | .2005 |
| 'Magic Island' | Small | Yellow | Marginal | Blue-Green | Sport | Med-Lavender | July into August | Heemskerk, Gerardus | .2011 |
| 'Magic Toy' | Large | Med-Green | Marginal | White | Hybrid | Pale-Lavender | June | McDonell, Harold | .2021 |
| 'Mai Tai' | Large | Dark-Green | - | - | Sport | - | - | Unknown | --NR-- |
| 'Maid in the Shade' | Large | Light-Green | Marginal | Yellow | Hybrid | - | July into August | Husemann, Jim | .2009 |
| 'Majordomo' | Large | Blue/Green | - | - | Unknown | Near-White | August | Deckert, Emile & Deckert, Jane | .2004 |
| 'Mama Bear' | Large | Light-Green | - | - | Hybrid | - | - | Schmidt, Bevie | .2009 |
| 'Mañana' | Large | Dark-Green | - | - | Unknown | Near-White | - | Tompkins, Chet & Ruh, Peter & Ruh, Jean | .2001 |
| 'Maniac' | Medium | Med-Green | Marginal | Green | Sport | Near-White | July into August | Schwarz, Jim | .2010 |
| 'Marilyn's Petticoat' | Small | Med-Green | | | Hybrid | Deep-Purple | August to September | Ragus, Gerhard & Ragus, Renate | .2021 |
| 'Marine' | Small | Blue/Green | Streaked | White | Sport | Med-Lavender | July into August | Gilligan, Madelon | .2015 |
| 'Mariposa' | Miniature | Med-Green | Streaked | Yellow | Hybrid | Med-Lavender | June into July | Dye, Kay | .2017 |
| 'Marlu's Carrie Lynn' | Small | Med-Green | - | - | Hybrid | Med-Lavender | July into August | Overhiser, Martin & Stegeman, Bev & Stegeman, Dave | .2014 |
| 'Marlu's Marla Jean' | Miniature | Light-Green | - | - | Hybrid | Pale-Lavender | July into August | Overhiser, Martin | .2014 |
| 'Marlu's Marshall' | Large | Blue/Green | - | - | Hybrid | Near-White | June into July | Overhiser, Martin | .2014 |
| 'Marlu's Sandra Jill' | Small | Yellow | - | - | Hybrid | Pale-Lavender | July into August | Overhiser, Martin & Stegeman, Bev & Stegeman, Dave | .2014 |
| 'Marnie's Delight' | Medium | Dark-Green | Medial | Yellow | Unknown | Med-Lavender | July into August | Kuenster, Rod | .2006 |
| 'Martini' | Small | Med-Green | - | - | Hybrid | Light-Purple | July | Zilis, Mark | .2009 |
| 'Maruba Iwa' | Small | Med-Green | - | - | Sport | Pale-Lavender | September | Unknown & Walek, Kevin | .2009 .2018 |
| '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 |
| 'Mary Scholl' | Large | Med-Green | Medial | Yellow | Sport | Pale-Lavender | June | Lamlein, Robert | .1999 |
| 'Me and My Shadow' | Medium | Blue/Green | Medial | Green | TC Sport | Near-White | July | Schwarz, Jim | .2003 |
| 'Mean Green Thing' | Medium | Med-Green | - | - | Sport | - | - | Fransen, Marco | --NR-- |
| 'Mean Joe Green' | Medium | Blue/Green | - | - | Hybrid | Med-Lavender | July into August | Zolock, Steve & Zolock, Sarah | .2008 |
| 'Megalodon' | Giant | Med-Green | | | Unknown | | | Unknown | --NR-- |
| 'Merci Marci' | Small | Blue/Green | Marginal | White | Unknown | - | July into August | Asch, Stuart | .2008 |
| 'Mercury Rising' | Medium | Yellow | | - | Unknown | Med-Lavender | July into August | Dye, Kay | .2020 |
| 'Mercy Me' | Medium | Dark-Green | - | - | Hybrid | Med-Lavender | June into July | McDonell, Harold | .2021 |
| 'Metallic Sheen' | Large | Dark-Green | - | - | Hybrid | Pale-Lavender | July into August | Zilis, Mark | .1999 |
| 'Metamorphosis' | Large | Blue/Green | - | - | Hybrid | Light-Purple | July into August | Kwick, Charles | .2017 |
| 'Michael's Legacy' | Small | Dark-Green | Marginal | White | Hybrid | - | July into August | Zolock, Steve & Zolock, Sarah | .1999 |
| 'Midnight at the Oasis' | Medium | Dark-Green | Medial | White | Sport | Med-Lavender | July into August | Naylor Creek Nursery & The American Hosta Society | .2019 |
| '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 |
| 'Midnight Oil' | Medium | Dark-Green | - | - | Hybrid | Light-Purple | July | Stegeman, Bev & Stegeman, Dave | .2004 |
| 'Midsummer Night's Green' | Large | Dark-Green | - | - | Hybrid | Med-Lavender | July into August | Goodwin, Randy | .2006 |
| 'Mighty Min' | Miniature | Med-Green | - | - | Hybrid | Pale-Lavender | June into July | Gilligan, Madelon | .2013 |
| 'Mighty Mini' | Small | Blue/Green | Marginal | Yellow | Sport | Light-Purple | June into July | Silvers, Bill | .2013 |
| 'Mighty Mite' | Small | Med-Green | - | - | Hybrid | Med-Lavender | August to September | Dean, Don | .2004 |
| 'Mighty Special' | Small | Blue/Green | Streaked | Yellow | TC Sport | Pale-Lavender | June into July | Silvers, Bill | .2013 |
| 'Milk Road' | Large | Blue/Green | - | - | Sport | Near-White | June into July | Van den Top, Jan | --NR-- |
| 'Millard Fillmore' | Large | Med-Green | - | - | Unknown | - | - | Ruh, Peter & Ruh, Jean | .2010 |
| 'Mill's Repechage' | - | Med-Green | - | - | Hybrid | - | - | Sneyers, Rob | --NR-- |
| 'Ming Dynasty' (O'Harra) | Large | Med-Green | - | - | Unknown | Pale-Lavender | July | O'Harra, Russ | .1999 |
| 'Mini Moon' | Miniature | Blue/Green | - | - | Hybrid | Near-White | - | Lachman, Wm & Lachman, Eleanor | --NR-- |
| 'Minnesota Nice' | Medium | Dark-Green | Medial | Yellow | Sport | Med-Lavender | July | Snyder, Ron | .1997 |
| 'Mint Condition' (Carlson) | Large | Med-Green | Marginal | White | Unknown | Med-Lavender | June into July | Carlson, Monty & Carlson, Julie | .2013 |
| 'Minute After a Rainy Sunset' | Medium | Light-Green | Streaked | Yellow | Sport | Pale-Lavender | July into August | McHugh, Ed | .2010 |
| 'Mirror Image' | Medium | Dark-Green | | | Unknown | | | Meyer, Bill | --NR-- |
| 'Mishmash' | Small | Med-Green | Streaked | White | Unknown | Near-White | August | Kuroishi Wildflower Farm & Van Eechaute, Danny | --NR-- |
| 'Miss Abbie' | Small | Blue/Green | - | - | Hybrid | Light-Purple | August | Schroeder, Bob & Schroeder, Barb | .2019 |
| 'Miss American Pie' | Medium | Dark-Green | - | - | Hybrid | Light-Purple | August to September | Wasitis, Chick | .2009 |
| 'Miss Ellie Fish' | Large | Yellow | - | - | Unknown | - | - | Hackbarth, Robert | .2015 |
| 'Miss Grace' | Medium | Med-Green | - | - | Unknown | - | July into August | Wrede, Arthur | .2005 |
| 'Miss Maddie' | Medium | Dark-Green | Streaked | Yellow | Sport | Med-Lavender | June into July | Simes, Naomi & Snyder, Ron | .1999 |
| 'Miss Mitzi' | Medium | Dark-Green | Marginal | White | Hybrid | Med-Lavender | June into July | Schroeder, Bob & Schroeder, Barb & Beilstein, Doug | .2016 |
| 'Miss Poland' | Small | Med-Green | Streaked | Yellow | Sport | Med-Lavender | June into July | Kijanska, Poll | .2019 |
| 'Missy Marie' | Large | Yellow-Gold | | - | Hybrid | Near-White | July | Husemann, Jim | .2020 |
| 'Misted Cove' | | | | | Unknown | | | Unknown | |
| 'Mister Green Genes' | Medium | Med-Green | - | - | Hybrid | Pale-Lavender | July into August | Goodwin, Randy | .2017 |
| 'Misty' (Goodwin) | Miniature | Light-Green | Marginal | Yellow | Unknown | Med-Lavender | July into August | Goodwin, Randy | .2019 |
| 'Mohrchen' | Medium | Dark-Green | - | - | Unknown | Med-Lavender | - | Camehl, Friedrich | --NR-- |
| 'Mojito' | Large | Med-Green | - | - | TC Sport | Pale-Lavender | August | Zilis, Mark | .2009 |
| 'Mom's Girl' | Large | Dark-Green | Streaked | Yellow | Unknown | - | - | Elslager, Ed | .2003 |
| 'Money Honey' | Medium | Yellow | - | - | Unknown | - | July into August | Malloy, Alex | .2003 |
| 'Monster Ears' | Medium | Med-Green | - | - | Sport | Near-White | July into August | Heemskerk, Gerardus | .2014 |
| 'Monument Circle' | Medium | Light-Green | Medial | White | Unknown | - | June into July | Crockett, Clyde | .1995 |
| 'Moolah' | Miniature | Dark-Green | Marginal | Yellow | Hybrid | Pale-Lavender | June into July | Goodwin, Randy | .2013 |
| 'Moongate Little Dipper' | Medium | Med-Green | - | - | Hybrid | Light-Purple | July | Solberg, Robert | .1996 |
| 'Mop Top' | Miniature | Dark-Green | - | - | Hybrid | Pure-White | - | Beilstein, Doug & Beilstein, Mardy | .2009 |
| 'Morning Star' | Medium | Yellow | Marginal | Green | Sport | Med-Lavender | July into August | Heemskerk, Gerardus | .2011 |
| 'Mosel' | Medium | Med-Green | - | - | Unknown | Med-Lavender | - | Klose, Heinz & Ruh, Peter & Ruh, Jean | .2008 |
| 'Mother of Invention' | Small | Med-Green | Marginal | Yellow | Unknown | - | - | Livingston, Ron | --NR-- |
| 'Mount Carmel' | Large | Med-Green | - | - | Unknown | Light-Purple | July | Wilkins, Dr Jim | --NR-- |
| 'Mount Daisen' | Large | Dark-Green | - | - | Hybrid | Pale-Lavender | June into July | Sugita, Hajime & Ruh, Peter & Ruh, Jean | .2005 |
| 'Mount Holyoke' | Medium | Med-Green | Marginal | Yellow | Hybrid | Near-White | July | Lachman, Wm & Lachman, Eleanor & Walek, Kevin | .2009 |
| 'Mountain Pride' | Giant | Med-Green | - | - | Unknown | - | July into August | Benedict, Dr Ralph (Herb) & Kuenster, Rod | .2010 |
| 'Mr. Asami Improved' | Medium | Med-Green | Marginal | White | Unknown | Light-Purple | August | Unknown & Asami, Hisatovo | --NR-- |
| 'Mr. Big' | Giant | Dark-Green | - | - | Unknown | Near-White | July | Purtymun, Charles & Ruh, Peter | .2010 |
| 'Munchkin Fire' | Miniature | Light-Green | - | - | Unknown | Med-Lavender | July | Goodwin, Randy | .2009 |
| 'Murasaki Ki Noka' | Medium | Light-Green | - | - | Unknown | Light-Purple | July | Unknown | --NR-- |
| 'Muresuzume' | Small | Dark-Green | - | - | Sport | Near-White | August | Unknown | --NR-- |
| 'Murphy's Golden Marge' | Medium | Yellow | - | - | Unknown | Pure-White | June into July | Zolock, Steve & Zolock, Sarah | .2001 |
| 'Mustang' | Small | Med-Green | - | - | Sport | Med-Lavender | June into July | Malloy, Alex | .2002 |
| 'Mutant Ninja' | Miniature | Dark-Green | Streaked | Yellow | Sport | Deep-Purple | July | Janssen, Bill & Walek, Kevin | .2009 |
| 'My Danish Hope' | Medium | Light-Green | Streaked | Blue-Green | Sport | Med-Lavender | August | Poulsgaard, Preben | .2018 |
| 'My Danish Sunshine' | Small | Light-Green | - | - | Sport | Near-White | July into August | Poulsgaard, Preben | .2018 |
| 'My Fine Feathered Friend' | Large | Med-Green | Marginal | Yellow | Sport | Near-White | July into August | Seaver, Charles | .2012 |
| 'My Gal Sal' | Medium | Yellow | Streaked | White | Sport | - | July into August | Freeman, Franc | .2009 |
| 'My Girl' | Medium | Med-Green | Marginal | White | Unknown | Pale-Lavender | June into July | Schwarz, Jim | .2012 |
| 'My Man Mark' | Giant | Med-Green | - | - | Hybrid | - | - | Schmidt, Bevie | .2009 |
| 'My Maria' | Small | Dark-Green | Medial | White | Sport | Deep-Purple | July into August | Sebright Gardens | .2018 |
| 'My Mom' | Medium | Dark-Green | Streaked | Yellow | Hybrid | Near-White | June | Kuenster, Rod | .2008 |
| 'My Precious' | Miniature | Med-Green | Marginal | Yellow | Sport | Light-Purple | July | Vandekinderen, Gino | --NR-- |
| 'My Sister Anita' | Small | Med-Green | - | - | Hybrid | Light-Purple | June into July | Gilligan, Madelon | .2017 |
| 'Mystery Mom' | Large | Blue/Green | Streaked | Speckles | Unknown | - | July into August | Elslager, Ed | .2005 |
| 'Mystic' | Small | Dark-Green | Streaked | Speckles | Hybrid | - | - | Malloy, Alex | .2000 |
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