Slug Proof Garden: Slug Resistant Perennials for a Slug Free Garden

by DerdriuMarriner

Prettifying gardens with perennials that are repellent to slugs is an easy, natural option for enjoying slug-free gardening.

Gardeners despair at the devastation wreaked upon their plants by slugs.

Certain perennials that are disagreeable to slugs form a natural barrier to exclude slugs from garden invasions.

Six slug-proof perennials, for a range of sunlight and shade conditions and temperature zones, are presented as natural, "green" remedies:
•bigroot geranium (Geranium macrorrhizum).
•fringed bleeding-heart, staggerweed, turkey corn or wild bleeding-heart (Dicentra eximia),
•Halcyon hosta (Hosta x tardiana 'Halcyon'),
•hellebore snow love (Helleborus x nigercors),
•monkshood (Aconitum carmichaelii).
•ornamental onion (Allium 'Globemaster)

Dusky slug (Arion subfucsus) consuming dandelion (Taraxacum):

Strategies for excluding slugs from gardens include nearby diversionary plants such as dandelions and barriers of slug-repugnant perennials.
Boulevard Park, Seattle, northwestern Washington
Boulevard Park, Seattle, northwestern Washington

Slugs in the garden: natural strategies for hastening slugs from gardens

 

The problem with slugs is that they relish gardens. They appreciate the edibility of fruits, ornamentals, and vegetables. With their voracious appetites, slugs easily partake their way through these favored food sources. Gardeners despair when day breaks upon the unmistakable evidences of slugs' nightly feastings.

Strategies for exiling slugs from gardens encompass chemical as well as natural measures. The concern with chemicals is that they often are toxic and fatal as well to accidental garden visitors, such as pets. Natural measures include surrounding garden plants with dry mulch, such as pine needles which repel slugs with their acidity. Strewing the soil with coffee grounds, copper plates, crushed egg shells, sand, or stone chips all solve the slug problem by desiccating them or gutting their sensitive bellies. Salt also dessicates slugs but is not desirable for a slug invasion as the soil salinity may be increased.

Three additional organic methods that are highly effective and cause no suffering to the slugs involve:

  1. Planting, at judicious intervals throughout the garden, red-leaved or red-stemmed and red-ribbed plants, such as Swiss chard (Beta vulgaris subsp. cicla), which shoo slugs from their vicinity, as red-leaved or red-ribbed plants are repugnant to slugs;
  2. Removing slugs to the compost pile, where the slugs will live a happy, satisfied life and eventually decompose at life's end along with the rest of the compost bin;
  3. Encircling the garden with slug-proof perennials that are known to disinvite these undesirable visitors.

Planting slug-free perennials as barriers effectively excludes pesky slugs from the garden as well as beautifies the garden vista. Although these perennials successfully shun slugs, they form a stunning and often fragrant enclosure around garden valuables. Following are slug-free perennial suggestions for various hardiness zones.

 

monkshood (Aconitum carmichaelii)

Mount Hijiri, Chūbu region, central Honshū island, Japan
Mount Hijiri, Chūbu region, central Honshū island, Japan

Zones 3 to 9 (-40 to 30 °F; -40 to - 1 °C): Full sun or partial shade

 

Aconitum carmichaelii, commonly known as monkshood, reaches a height of 7 feet (2 meters) with a spread of 24 to 36 inches (60 to 90 centimeters).

White to mauve helmet-shaped flowers grow densely in spikes against dark green, toothed, leathery leaves which curl to reveal pale undersides.

The Royal Horticultural Society has bestowed its prestigious Award of Garden Merit (AGM) upon two monkshood cultivars:

  • Aconitum carmichaelii (Arendsii Group) 'Arendsii' in 2002, and
  • Aconitum carmichaelii (Wilsonii Group) 'Kelmscott' in 1993.

Caution should be exercised, as:

  • contact with Aconitum foliage may cause skin irritations;
  • ingestion of any part of Aconitum plant may provoke high toxicity.

 

bigroot geranium (Geranium macrorrhizum)

Essential oil extracted from Geranium macrorrhizum is named Zdravets (zdrave "health") in Bulgaria.
Essential oil extracted from Geranium macrorrhizum is named Zdravets (zdrave "health") in Bulgaria.

Zones 4 to 9 (-30 to 30 °F; -34 to - 1 °C): Partial shade or full sun

 

Geranium macrorrhizum, commonly known as bigroot geranium, reaches  a height of 20 inches (50 centimeters), with a generous spread of 40 inches (100 centimeters).

Dense clusterings of flowerheads open as gorgeous pink to purple-red flowers.

Geranium macrorrhizum combines the double threat of dissuading both deer and slug inquirers from entering the garden.

Two cultivars of bigroot geranium have been recognized with the Royal Horticultural Society's Award of Garden Merit (AGM):

  • Geranium macrorrhizum 'Ingwersen's Variety' in 1993, and
  • Geranium macrorrhizum 'White-Ness' in 2006.

 

 

fringed bleeding-heart (Dicentra eximia)

New World plant native to Appalachian areas of Pennsylvania, south into Maryland, North Carolina, and Tennessee.
New World plant native to Appalachian areas of Pennsylvania, south into Maryland, North Carolina, and Tennessee.

Zones 5 to 9 (-20 to 30 °F; -29 to - 1 °C): Full sun or partial shade

 

Dicentra eximia, commonly known as fringed bleeding-heart, staggerweed, turkey corn or wild bleeding-heart, reaches a height of 12 to 26 inches (30 to 65 centimeters) with a spread of 20 to 40 inches (50 to 100 centimeters).

From mid-summer to autumn, flowers open in sprays of pink or white heartshaped flowers which contrast strikingly with the finely divided, blue-green leaves.

Caution should be exercised, as:

  • contact with Dicentra foliage may activate skin allergies;
  • ingestion of any part of Dicentra plants may provoke mild stomach upsets.

 

halcyon hosta (Hosta x tardiana 'Halcyon'):

borders well with variegated liriope (Liriope muscari 'Variegata')
Tardiana hostas (Hosta x tardiana) number among the hostas that are slug resistant.
Tardiana hostas (Hosta x tardiana) number among the hostas that are slug resistant.

Zones 6 to 10 (-10 to 40 °F; -23 to 4 °C): Partial shade or full shade

 

Hosta x tardiana 'Halcyon,' commonly known as Halcyon hosta, reaches a height of 16 inches (40 centimeters) with a spread of 16 to 20 inches (40 to 50 centimeters).

Lavender-grey flowers open in bell shapes above heart-shaped blue-grey leaves.

Hostas are not accepted or rejected categorically by slugs. Tardiana hostas number among Hosta species which are undesirable to slugs. Other slug-resistant hostas include:

  • Hosta rupifraga
  • H. sieboldiana
  • H. tokudama.

Hostas which are prone to slug attention include:

  • H. crispula
  • H. hypoleuca
  • H. kikutii
  • H. pycnophylla
  • H. ventricosa.

 'Halcyon' received the Royal Horticultural Society's Award of Garden Merit (AGM) in 1993.

 

Allium 'Globemaster'

The odor of plants in the Allium genus is repugnant to slugs.
The odor of plants in the Allium genus is repugnant to slugs.

Zones 7 to 9 (0 to 30 °F; -18 to - 1°C): Full sun

 

Allium 'Globemaster,' commonly known as ornamental onion, reaches a height of 24 to 36 inches (60 to 90 centimeters), with a spread of 6 to 12 inches (15 to 30 centimeters).

Flowers open as deep violet in 6- to 8-inch (15- to 20-centimeter) wide flowerheads, perched like globes atop grey-green stems.

The Royal Horticultural Society bestowed upon Allium 'Globemaster' its prestigious Award of Garden Merit in 1995.

 

'Valentine Green' Christmas rose (Helleborus x nigercors 'Valentine Green')

J.T. Wall is credited with first valid description of Helleborus x nigercors, published in Gardeners' Chronicle in 1934.
J.T. Wall is credited with first valid description of Helleborus x nigercors, published in Gardeners' Chronicle in 1934.

Zones 7 to 10 (0 to 40 °F; -18 to 4°C): Partial shade or full shade

 

Helleborus x nigercors, commonly known as hellebore snow love, is equiproportional, with both a height and a spread of 24 inches (60 centimeters).

Helleborus x nigercors is a cross of Hellebrous argutifolius, commonly known as Corsican hellebore, with its large, 2-inch (5 centimeter) wide, green flowers, and Helleborus niger, commonly known as Christmas rose, with large, up to 4-inch (10-centimeter) wide, pale white flowers flushed with light green or pink.

Helleborusnigercors flowers open as saucer shapes of white or white tinted with pink or blue green and bloom from winter to spring.

Helleborus x nigercors also is dissatisfactory to white-tailed deer, so a garden noticed by deer and slugs will be disenchanted quickly of these visitors with the addition of this plant.

Caution should be exercised, as:

  • contact with Helleborus sap may cause skin irritations;
  • ingestion of any part of Helleborus plants may provoke severe discomfort.

 

great grey slug (Limax maximus) feeding on a large piece of tomato specifically set out for slug sustenance in backyard in Maryland:

Leaving treats in places distant from a garden is a successful natural remedy.
Slugs like tomatoes.
Slugs like tomatoes.

Slug-free gardens: the visual beauty of a natural solution

 

For gardens overrun by slugs, there are many options.

  • Enclosing gardens with slug-proof perennials provides an effective, natural solution to the problem.

Perceiving the presence of disagreeable plants, slugs trespass no further and either find alternatives, such as nearby dandelion fields, or die searching.

  • A tangential remedy is to relocate slugs to the compost pile, where their contributions to decomposition excel.

In turn, gardeners are relieved easily of pests and derive further enjoyment from the increased visual beauty ensuing from the spectrum of slug-proof perennials.

 

slug consuming a blade of grass

Grapeview, Mason County, west central Washington
Grapeview, Mason County, west central Washington

Acknowledgment

 

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

 

Like Hosta tardiana 'Halcyon,' Hosta ventricosa is slug-resistant.

Hardy to zone 5, Hosta ventricosa flowers from July to July and is not frost tender.
Hardy to zone 5, Hosta ventricosa flowers from July to July and is not frost tender.

Image Credits

 

Boulevard Park, Seattle, northwestern Washington: Cheryl Moorehead, Bugwood.org, CC BY 3.0 US, via Forestry Images @ https://www.forestryimages.org/browse/detail.cfm?imgnum=5191039&

Mount Hijiri, Chūbu region, central Honshū island, Japan: Kumaapr9, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Torikabuto_01.jpg

Essential oil extracted from Geranium macrorrhizum is named Zdravets (zdrave "health") in Bulgaria.: Hardyplants at English Wikipedia, Public Domain, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Geranium_macrorrhizum_flowers.jpg

New World plant native to Appalachian areas of Pennsylvania, south into Maryland, North Carolina, and Tennessee.: DM (dmott9), CC BY-ND 2.0, via Flickr @ https://www.flickr.com/photos/dmott9/3553614344/

Tardiana hostas (Hosta x tardiana) number among the hostas that are slug resistant.: Ed (Goosefriend), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/gooseotter/4781606547/

The odor of plants in the Allium genus is repugnant to slugs.: Gail Frederick, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/galfred/525467177/

J.T. Wall is credited with first valid description of Helleborus x nigercors, published in Gardeners' Chronicle in 1934.: Kenpei, CC BY-SA 3.0, via Wikimedia Commons @ https://nl.wikipedia.org/wiki/Bestand:Helleborus_x_nigercors_Valentine_Green1.jpg

Slugs like tomatoes.: Maryland Pride, CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Maryland_Great_Grey_Slug.jpg

Grapeview, Mason County, west central Washington: Christine Majul (photogirl7.1), CC BY-SA 3.0, via Flickr @ https://www.flickr.com/photos/kitkaphotogirl/2897348352/

Hardy to zone 5, Hosta ventricosa flowers from July to July and is not frost tender.: Tadesse, CC BY-SA 2.0 DE, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Hosta_ventricosa1Tadesse.jpg

dandelion field in the Netherlands: Rene Mensen (Alias 0591 from the Netherlands), CC BY 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Field_of_dandelions_(5659006546).jpg

 

Sources Consulted

 

"Allium 'Globemaster' AGM." Royal Horticultural Society > Plants > Plant Selector. 2011. The Royal Horticultural Society. Web. www.rhs.org.uk

  • Available at: http://apps.rhs.org.uk/plantselector/plant?plantid=97 

Brickell, Christopher, and Judith D. Zuk, eds. The American Horticultural Society A-Z Encyclopedia of Garden Plants. New York: DK Publishing, 1996.

"Dealing with Slugs in the Hosta Garden." Perfect Perennials. Perfect Perennials Nursery. Web. perfectperennials.tripod.com

  • Available at: http://perfectperennials.tripod.com/id7.html

Flora: A Gardener’s Encyclopedia. Volumes I-II. Portland OR: Timber Press, 2003.

Lancaster, Roy. Perfect Plant Perfect Place: The Surest Way to Select the Right Outdoor and Indoor Plants. London-New York-Sydney-Moscow: Dorling Kindersley, 2002.

"RHS AGM Listing May 2013 (Ornamentals)." Royal Horticultural Society > Plant Awards > List of plants with the AGM. May 2013. The Royal Horticultural Society. Web. www.rhs.org.uk

  • Available at: http://www.rhs.org.uk/Plants/Plant-trials-and-awards/Plant-awards/AGM-plants

"Slug Resistant Plants." The Gardeners Guild > Gardening Tips. The Gardeners Guild (TGG). Web. www.thegardenersguild.co.uk

  • Available at: http://www.thegardenersguild.co.uk/Slug_resistant_plants.html

Symondson, William O.C. “Slug Control.” Cardiff School of Bioscences > StaffInfo > Slugs. October 1996. Cardiff University. Web. www.cardiff.ac.uk

  • Available at: http://www.cardiff.ac.uk/biosi/staffinfo/wocs2.html

 

the end which is also the beginning
the end which is also the beginning

Two volume set covering more than 20,000 plants from all around the world. Beautifully illustrated ~ Available via Amazon

Accompanying CD-ROM enables a gardener to choose plants by group, hardiness zone, flower, color, and flowering season.
Flora: A Gardener's Encyclopedia 2 volume set , vol 1 A-K vol 2 L-Z

American Horticultural Society's essential reference for all gardeners, from novices to experts ~ Available via Amazon

More than 15,000 individual entries, embellished with 6,000 full-color photographs and illustrations.
American Horticultural Society A to Z Encyclopedia of Garden Plants

Me and my purrfectly purrfect Maine coon kittycat, Augusta "Gusty" Sunshine

Gusty and I thank you for reading this article and hope that our product selection interests you; Gusty Gus receives favorite treats from my commissions.
DerdriuMarriner, All Rights Reserved
DerdriuMarriner, All Rights Reserved
Updated: 11/12/2024, DerdriuMarriner
 
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