Leucanthemum in winter: which varieties of Leucanthemum are hardy?
Not all daisy species are winter hardy. At the end of the summer, some daisies will need protection, whilst others can be left to overwinter.
In order for some types of daisies (Leucanthemum) to survive the cold, winter months, certain measures must be taken. Read on to find out which species of Leucanthemum are winter hardy, whether daisies can overwinter in pots, as well as everything else you will need to consider for getting your Leucanthemum through the winter.
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Which species of Leucanthemum are winter hardy?
The common name daisy is used to refer to several genera within the Asteraceae family. Here we focus on the Leucanthemum species and varieties that are able to withstand the coldest winters. The hardiness rating indicates in which temperature range the respective species can survive the winter in the UK. Some beautiful hardy perennial daisies include:
- Oxeye daisy (Leucanthemum vulgare): endures temperatures lower than -20°C, hardiness rating H7
- Shasta daisy (Leucanthemum x superbum): -15°C to -10°C, hardiness rating H5
- Max chrysanthemum (Leucanthemum maximum): -20°C to -15°C, hardiness rating H6
- Grass leaf oxeye daisy (Leucanthemum graminifolium): -20°C to -15°C, hardiness rating H6
- Oxeye daisy (Leucanthemum ircutianum syn. Leucanthemum praecox): – 20°C to – 15°C, hardiness rating H6
Tip: Despite being called daisies, the African daisy (Osteospermum spp.), Moroccan daisy (Rhodanthemum hosmariense), painted daisy (Tanacetum coccineum) and marguerite daisy (Argyranthemum frutescens) do not belong to the Leucanthemum genus. The painted daisy has a hardiness rating of H7, so is able to endure temperatures lower than -20°C, whilst the Moroccan daisy can withstand frosts down to -10°C (H4). Overwintering marguerite daisies requires extra care, since they only tolerate the low, single-digit temperatures of a milder winter. To protect marguerite and Moroccan daisies and help them through the coldest winters, cover the soil around the daisy with leaves or fir branches. African daisies will require a little more winter protection since they are not hardy in the UK. Find out how to grow, care for and overwinter African daisies in our dedicated article.
How best to overwinter Leucanthemums
Whilst hardiness ratings are usually fairly accurate, they cannot always be taken as a certainty. A Leucanthemum’s winter hardiness is dependent on several other non-genetic factors, including care practices.
The type of fertiliser you use plays a key role in preparing daisies for winter. Potassium is an important nutrient which influences a plant’s frost resistance by lowering the freezing point and thus serving as a natural antifreeze. Therefore, applying an organic, potassium-rich fertiliser, such as our Plantura Autumn Lawn Feed, in August and September can help. Do not fertilise too late in the autumn as plants cannot absorb nutrients as effectively at lower temperatures. In addition to providing the correct nutrients, it is important to prevent waterlogging. In mild, rainy winters, waterlogged soil can cause root rot, which will kill the plant even without frost.
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Tip: Be careful not to fertilise with nitrogen in late summer and early autumn, as this will encourage more leaf growth and reduce the Leucanthemum’s winter hardiness. At this time of year, it is important to slow down growth so that the daisy prepares itself for its winter dormancy. Therefore, only use potassium fertilisers at this later time of year.
Overwintering daisies in a bed
Given the right Leucanthemum care, hardy species such as Leucanthemum vulgare can quite easily survive the winter outdoors in a bed. Planting your daisies in a wind-protected location will help ensure they last through the winter. In addition, for those with a hardiness rating of H5 or H6, covering the soil around the daisy with leaves or fir branches will help with insulation. It is best not to use damp or soaking material here, as these can increase the risk of fungal infections. When cutting back your daisies in the winter, take care not to cut them too close to the ground. No shorter than 15cm is optimum.
Overwintering Leucanthemum in a pot
You can also overwinter daisies in a pot which you move to a warmer location when temperatures drop. Leucanthemum in pots will unlikely survive being overwintered outdoors, since there is not enough soil around the roots to provide insulation. In severe frost, the pot could simply freeze through which would kill even the hardiest oxeye daisy.
To overwinter Leucanthemum in pots, cut back two thirds of the daisy in the autumn. At the first frost, bring the pot into a frost-free, cool and light room where it can be left to overwinter. The room should be below 10°C, so cold garages, hallways and unheated greenhouses are usually suitable. Keep the pot away from direct sunlight as this can encourage premature blooming, particularly if the room is too warm. As spring approaches, begin to acclimatise the daisy to the warming temperatures by bringing the pot into a warmer, brighter spot in your home. From around April, or after the last frost, gradually move the pot back outdoors.
Even though many daisies are able to survive the winter, it is best to wait until spring to plant them. Find out everything you need to know about planting Leucanthemum in our dedicated article.
