Mentha suaveolens Ehrh., Round-leaved Mint
Account Summary
Introduction, garden escape, very rare. Submediterranean-subatlantic.
1939; Praeger, R.Ll.; Belcoo, Lough Macnean.
Growth form and preferred habitats
Another rhizomatous, aromatic, vaguely apple-scented mint of damp places, M. suaveolens is a rather stout or sturdy perennial with erect stems, 40-100 cm tall, pale green in colour, usually quite heavily branched above the middle. The stems are very variably hairy, ranging from sparsely to densely clothed with white, simple eglandular hairs. The leaves, 3.0-4.5 cm, ovate-oblong to sub-rotund, are strongly rugose (sage-like), pubescent, margins serrate, grey-or white-tomentose beneath. Flowering occurs in August and September, the inflorescence of numerous congested whorls, forming a terminal spike, interrupted below and usually branched. The calyx is campanulate, hairy and the corolla whitish or pink and hairy outside (Sell & Murrell 2009). Although it is sometimes referred to as 'Apple-scented Mint', the aroma or flavour is described by Grieve (1931) as rather like Spear Mint (M. spicata), but stronger. Other descriptions consider it has a 'fruity' mint flavour.
Growth of the plant is rapid and its rhizomatous spread enables it to quickly form extensive clonal patches that may prove excessively invasive in a garden setting.
Typical habitats are either coastal ditches, or naturalised as garden escapes or discards on damp, lowland roadsides and waste places inland (K. Walker, in: Preston et al. 2002). It is also associated with churchyards and the sites of ruined monasteries, monks having cultivated it for medicinal as well as for culinary use (Grieve 1931; Chater 2010).
British and Irish status
M. suaveolens is regarded by some as a native species in coastal parts of Britain, but probably it is only so in parts of SW England and Wales (K. Walker, in: Preston et al. 2002). The current author (RSF) cannot locate any convincing proof of native status for this species: there does not appear to be any fossil evidence (Godwin 1975) and since the herb has a very long history of garden cultivation and culinary use, reliance on findings dating from John Ray's excursions in the 1660s really do not prove indigenous origin (Pearman 2017).
In his Flora of Cardiganshire, Chater (2010) quotes Salter (1935) on this mint, saying, "Occurs usually, but not always, in the neighbourhood of cottages, having been grown, along with other species of Mint, by the old herbalists." Salter gave a dozen localities. Chater then refers to more recent records, "six other records since 1970 from waste ground, road verges and churchyards" and, later, "Whether it is native in any of these sites is uncertain…". He then maps them all as aliens. The Flora of Cornwall, on the other hand, treats M. suaveolens as native without any reservations, describing it as, "scattered across Cornwall alongside roads and streams and on waste ground" (French 2020).
Elsewhere in Britain, and everywhere in Ireland, M. suaveolens is very clearly accepted as being an introduced alien and a garden escape or discard (K. Walker, in: Preston et al. 2002).
Fermanagh occurrence
There are only three very old records for this garden mint in the Fermanagh Flora Database, and none at all from the post-1975 period when so much more recording effort has taken place in the VC. This suggests to the current author (RSF) and RHN, that this mint really is rare, but it could also reflect hesitancy on the part of field recorders to distinguish this species. It is not easy to separate this plant from its hybrid with M. spicata (M. × villosa (Apple-mint)), although there is in fact only one 1997 record of this hybrid in Fermanagh. M. suaveolens is a smaller plant than M. × villosa, its leaves more finely toothed and the flowering spikes are narrower, less than 10 mm wide (Halliday 1997).
The Fermanagh habitats of Round-leaved Mint are listed in the Revised Typescript Flora as, "waste ground, roadsides and a canal bank". The details of the other two records for the species are: near Lisnarrick, 1949, R. Mackecknie; and by the Old Ulster Canal near Gortnacarrow Bridge, 1950, MCM & D.
Irish occurrence
For a local comparison, the FNEI 3 also lists relatively few records of M. suaveolens, ie around 16 in the post-1938 period in total for the three NE Irish VCs (H38-H40).
The Cat Alien Pl Ir describes M. suaveolens as an occasional garden escape, persistent in abandoned gardens and in a few situations along river banks. It lists occurrences in 34 of the 40 Irish VCs, the exceptions being Cos Kildare (H19), Westmeath (H23), Leitrim (H29), Monaghan (H32) and Donegal (H34, H35). The New Atlas hectad map displays the fact that recent Irish records are very scattered and sparse, the frequency and pattern being similar to that in C & N England.
British occurrence
In Britain, M. suaveolens has been recorded from the Channel Isles and the Scilly Isles (VC 1a) to Orkney (VC 111) in the far north. The New Atlas hectad map shows it is most concentrated in the SW of England and Wales, but quickly becomes scattered and scarce northwards and eastwards until in Scotland it is very rare and almost entirely coastal.
There is also evidence from hectad data in the two BSBI Atlas surveys (Perring & Walters 1962; Preston et al. 2002), that occurrences of M. suaveolens have been in decline for at least 50 years. However, some of these apparent losses may have arisen through early records of M. suaveolens representing over-recording, due to errors in the identification of M. × villosa and, in particular, with a variety of the latter referred to as nv. alopecuroides (Hull) Briq. (Brewis et al. 1996; K. Walker, in: Preston et al. 2002).
European and world occurrence
This variable species was originally restricted to Europe and the adjacent part of N Africa but, being a culinary herb, its distribution is insufficiently known since it has been spread by garden cultivation from its unknown indigenous origin. It has been introduced to N & S America and to New Zealand (Hultén & Fries 1986, Map 1616).
Uses
Apple-scented Mint (sometimes mistakenly referred to as 'Apple Mint' which is more accurately M. × villosa nv. alopecuroides) or 'Round-leaved Mint' is often regarded as a substitute for, or is even used in preference to, M. spicata, Spear Mint, primarily because it has a sweeter flavour than the latter, but secondly on account of its greater ability to resist the pathogen, Mint Rust (Webb et al. 1988).
Round-leafed Mint has been frequently used as a domestic herbal remedy, like other mint species being valued mainly for its antiseptic properties and its beneficial effect on digestion. Again, as with other cultivated mints, a tea made from the leaves has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments (Grieve 1931; Foster & Duke 1990).
Names
The Latin specific epithet 'suaveolens' is a combination of 'suāvis' meaning 'sweet' or 'agreeable' and 'oleo', 'to emit a smell', and thus 'sweet-scented' (Gilbert-Carter 1964; Gledhill 1985).
English common names include 'Apple-scented Mint', 'Apple Mint', 'Pineapple Mint', 'Round-leaved Mint', 'Woolly Mint' and 'Horse Mint' (Britten & Holland 1886).
Threats
None.