Hebes: which varieties survive winter?
In short: hebes are evergreen shrubs from New Zealand, now classified by botanists in the genus Veronica. They flower for a long time and attract pollinators, but their hardiness varies widely. Most are rated H4 by the RHS (−5 to −10 °C), and an English trial showed that a cold snap at −8 °C can destroy many of them. In Belgium, prefer small-leaved kinds ('Pagei', topiaria, rakaiensis, 'Red Edge', 'Pewter Dome'), plant in spring, in full sun and very free-draining soil, and never prune them hard. The large pink- or purple-flowered varieties are more beautiful… and more fragile.
They are sold everywhere, in pots, in autumn as well as spring, often labelled "hardy". Yet hebes are southern-hemisphere shrubs, and many Belgian gardeners have seen a fine specimen turn black after a slightly cold winter. The good news is that the difference between a hebe that survives and one that freezes is fairly predictable. This article relies on three solid sources: the Royal Horticultural Society (RHS) growing advice, its 2021-2023 trial that went through a harsh winter, and nine years of observations by Oregon State University.
Hebe or veronica: the name has changed
The genus is named after Hebe, the Greek goddess of youth, who served drinks to the gods (Hutchinson, 2025). It has about 90 to 100 species. Almost all come from New Zealand, where it is the largest plant genus; one species lives on the island of Rapa in French Polynesia, and two others also grow in South America and the Falklands (NZPCN, n.d.; Hutchinson, 2025).
In 2007, three botanists showed, with DNA analyses, that hebes form a branch inside the genus Veronica, the speedwells of our meadows. Keeping them in a separate genus would have made Veronica inconsistent. So they renamed hebes Veronica section Hebe (Garnock-Jones et al., 2007). The RHS followed: its recent trial speaks of "shrubby Veronica (formerly Hebe)", and its advice pages note that labels often still use the old name (RHS, n.d.-a). Not all botanists applauded: some New Zealand specialists feel the merger loses information.
In the garden, both names coexist. Hebe 'Great Orme' and Veronica 'Great Orme' are the same plant. In Dutch, they are called struikveronica.
What the 2022-2023 winter taught the RHS
From 2021 to 2023, the RHS grew 126 different hebes in its trial garden at Wisley, south of London, and 109 at Harlow Carr, in the north of England (Hutchinson, 2025). It was its first hebe trial since 1980; the previous one had lost 52 entries in the winter of 1981.
History repeated itself. On 15 December 2022, after a very mild start to winter, the temperature fell to −8.1 °C at Wisley on a clear night, with no gradual hardening-off. In January 2023, a second cold spell lasted ten days. The result is described bluntly: complete devastation of the trial at Wisley. At Harlow Carr, further north, there were very few losses. The cold arrived gradually, the minimum was only −5.3 °C, the soil had been mixed with gravel and the plants were sheltered within a mixed border (Hutchinson, 2025).
At the end of the trial, the panel took clear decisions:
- Award withdrawn (Award of Garden Merit) from 18 varieties, including two of the best-selling hebes: 'Great Orme' (pink flowers) and 'Midsummer Beauty' (lilac flowers), as well as 'Caledonia', 'Pascal', 'Pink Elephant', 'Neil's Choice' and 'White Gem'.
- Award confirmed notably for 'Red Edge', Veronica topiaria, V. rakaiensis, V. albicans, V. pinguifolia 'Pagei', V. ochracea 'James Stirling', 'Mrs Winder' and 'Wiri Cloud', described as "the hardiest pink-flowering hebe". 'Pewter Dome' even moves up to H5.
- New awards (2024) for nine varieties, including V. salicifolia 'Adel White' (H5), 'Mint Chocolate' and 'Wiri Mist'.
It was not an exceptional winter that caused this damage: −8 °C is a cold that Belgium regularly experiences. That is what makes this trial so useful for us.
Small leaves, greater resistance
Oregon State University followed more than 200 hebes outdoors at Aurora from 2000 to 2009 (Bell, n.d.). The most serious damage occurred during early frosts (November) or late frosts (February, after a mild spell), between −4 and −7 °C. Similar cold in midwinter, on hardened plants, caused no visible damage. The timing of a frost matters more than the minimum temperature.
The author draws a general rule from it, which the author calls imperfect: large-leaved hebes are less hardy, small-leaved ones more resistant. Whipcord hebes, with leaves reduced to scales, did not react to Oregon winters. Among the most resistant were 'Emerald Gem', H. topiaria, 'Youngii' and 'Boughton Dome'; among the most damaged, 'Amy', 'Patty's Purple' and 'Silver Queen', all of which have large or variegated leaves.
The rule has exceptions: 'Emerald Gem' and 'Youngii', two small hebes that were flawless in Oregon, are among the 18 varieties whose award the RHS withdrew after the 2022-2023 winter (Hutchinson, 2025). Small leaves improve the odds; they guarantee nothing.
The RHS points the same way: hebes with green, purple or silver leaves are the hardiest, variegated ones are not fully hardy (RHS, n.d.-a).
| Type of hebe | Examples | RHS rating | In Belgium |
|---|---|---|---|
| Small leaves, rounded habit | 'Pagei', topiaria, rakaiensis, 'Red Edge', 'Mrs Winder' | H4 | the safest choice, in full sun |
| Silver or glaucous foliage | albicans, 'Pewter Dome', 'Quicksilver' | H4 to H5 | very good in dry soil and by the sea |
| Large leaves, long flower spikes | 'Great Orme', 'Midsummer Beauty' | H4 (award withdrawn for both) | in a sheltered corner, against a south wall |
| Variegated and coloured hybrids | 'Silver Queen', 'Amy' | H3 for 'Silver Queen' (1 to −5 °C) | in a pot, moved frost-free for winter |
RHS ratings read as follows: H3 = 1 to −5 °C, H4 = −5 to −10 °C, H5 = −10 to −15 °C (RHS, n.d.-b). An H4 plant survives an average Belgian winter, not necessarily a cold one.
Where and when to plant a hebe
- Full sun. Hebes do not last long in shade, damp soil or very cold spots (RHS, n.d.-a).
- Free-draining soil. They like moderately fertile soil and tolerate chalk. They hate heavy clay and standing water: on heavy soil, plant on a mound or in a raised bed. At Harlow Carr, gravel mixed into the soil helped them survive (Hutchinson, 2025).
- In spring. The RHS advises planting in April or May, and never in winter (RHS, n.d.-a). A hebe bought in November is better off spending the winter in its pot, under shelter.
- Spacing. About 90 cm between plants in a border; 30 cm for a low hedge, 45 cm for larger varieties.
- By the sea. Hebes cope well with salty wind; silver varieties are the best for the coast.
- In a pot. Roots are less protected from cold: a potted hebe freezes more easily than one in the ground. Move the pot close to a wall and protect it from winter rain.
Small rounded hebes make good edging in front of hardy geraniums or taller shrubs such as viburnums.
Prune (little) and care
This is the most common mistake: cutting a leggy hebe back into old wood. The RHS is clear: hebes respond poorly to hard pruning and often fail to regrow from woody stems (RHS, n.d.-a). Good practice:
- deadhead spent spikes as they fade, which prolongs flowering and keeps the plant tidy;
- if needed, give a light trim with shears to restore the shape, preferably in spring once frosts are over;
- after a winter that has scorched the foliage, wait for growth to restart (April-May) before cutting, to see what regrows.
An old, leggy hebe is easier to replace than to rejuvenate: hence the value of cuttings.
Take cuttings to secure the next generation
Hebes root very easily. The RHS recommends semi-ripe cuttings from July to September (RHS, n.d.-a): current-year stems whose base is starting to harden. Do not overwater them, they rot quickly. Keep them over winter in a frost-free, well-ventilated place, plant them out the following spring: they should flower about two years later.
Keeping two or three cuttings under cover every autumn is the best insurance for fragile varieties.
Diseases and pests
- Root rot in heavy, wet soil: this is the first cause of death, even before frost.
- Downy mildew and leaf spots, especially under poorly ventilated glass or on variegated types in soil that is too dry or too wet.
- Aphids on young shoots: usually harmless.
- Xylella fastidiosa: hebe is one of the nine high-risk host plants of this bacterium, which devastates olive trees in southern Italy (RHS, n.d.-a). It is subject to strict quarantine rules in Europe. Buy plants with a plant passport, from a reputable seller, and be wary of plants brought back from holidays.
A shrub for pollinators
Hebes flower for a long time, often from June into autumn, with white, pink, mauve or blue spikes that bees and butterflies readily visit. Some varieties such as 'Mrs Winder' are grown mainly for their purple winter foliage. With their evergreen leaves, they give structure to borders in every season, provided they have been well chosen.
Sources
- Bell, N. (n.d.). Hebe landscape evaluation. Oregon State University Extension. https://horticulture.oregonstate.edu/hebe-landscape-evaluation
- Garnock-Jones, P., Albach, D., & Briggs, B. G. (2007). Botanical names in Southern Hemisphere Veronica (Plantaginaceae): sect. Detzneria, sect. Hebe, and sect. Labiatoides. Taxon, 56(2), 571-582.
- Hutchinson, N. S. (2025, January 19). Trial of shrubby Veronica (formerly Hebe) 2021-2023 [Presentation]. Nederlandse Dendrologische Vereniging. https://dendrologie.nl/wp-content/uploads/2025-01-18-Hebe.pdf
- NZPCN. (n.d.). Hebes. New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/vascular/flowering-plants/dicots/hebes/
- RHS. (n.d.-a). How to grow hebes (shrubby veronica). Royal Horticultural Society. https://www.rhs.org.uk/plants/hebe/growing-guide
- RHS. (n.d.-b). RHS hardiness rating. Royal Horticultural Society. https://www.rhs.org.uk/plants/trials-awards/award-of-garden-merit/rhs-hardiness-rating