Is this plant hardy? the most commonly asked question in the garden centre.
What this does this mean? as a grower I think it means, would this plant survive a normal British winter. It should be able to stand the rain, wind and frost (down to -6).
A normal winter will depend on where you live, a Scottish winter would be different to one in the south, living in a town is warmer than the country and sea level is warmer than the top of the Pennines.
In large towns the heat from the buildings can create a warmer climate, I would describe this as urban hardy and you will be able to grow a different range of plants to someone who lives in the nearby countryside.
You can check the plants hardy rating online, but even this can be misleading, plants that can take very low winter temperatures can struggle to adapt to our climate of mild winters and late spring frosts.
This is where local knowledge is more important than books or the internet, I would ask your local nursery or garden centre for advice, or have a look in your neighbours garden to see what is surviving.
Plants are very adaptable so a lot of the old rules about plant types no longer apply. You can get outdoor plants like campanulas and hellebores sold as house plants and houseplant cyclamen sold as autumn bedding.
Check the label
Check the plant label to see if it mentions what temperature the plant needs, some common descriptions are
Tender
Most likely to be houseplant and not likely to grow outside.
Half-hardy
Basically, a houseplant or summer plant often not expected to survive the winter. In urban or coastal areas it might survive.
Hardy
An outdoor plant that should survive a normal British winter, there are various degrees of hardiness, very hardy can survive any winter.
Perhaps the best source of information is the R.H.S. website, use the plant finder and check out the hardiness rating.
Bear in mind a lot of new plants may not have a hardiness rating, nobody knows how hardy they are. Although plants are tested around the world they often react differently in your garden.
When out shopping check the plant description and any attached labels
Learn to read the plant labels, sometimes they are helpful but you may have to read between the lines, to see what they are not telling you.
This is your first line of defence and if you see any of the following take care.
Protect from frost
This is probably a summer-flowering plant, don’t plant out too early (May – June onward) it should grow and flower through the summer before dying in the autumn. It may also apply to plants that live longer but need some protection from severe weather, olive trees and tree ferns for instance
Temperature
A lot of plants are imported and the labels may only have symbols on them, one of the most important is the temperature range.
Minimum 5°C, Maximum 15°C: This plant likes a cooler location with temperatures between 5 and 15°C. these could be bedding plants or tender shrubs you might find them on summer bedding, patio plants, Geraniums, dahlias etc
Minimum 15°C, Maximum 25°C: This will need to keep as house plant or summer patio plant.
Minimum 20°C, Maximum 35°C: This plant likes to be warm and needs to be kept warm at room temperature or above.
You need to check the labels and try to understand what they mean, unfortunately, they tend to have symbols and minimal instructions.
If in doubt check online.
Here is an example of a Cordyline label, the first symbol shows sun or shade meaning it’s not fussy.
The second suggests you should water once a week not to be taken literally or it would soon be over-watered in the winter and dry out in the summer, I think they mean to keep it on the dry side.
The third symbol means to throw something at it once a month, I presume they mean fertiliser but only in the summer.
The fourth tells us that this is a hardy cordyline and you can plant outside.
Finally, it looks like you should not feed your plant but what they mean is don’t eat it.
This hardy fern label is slightly more helpful, the first symbol is sun or shade meaning it’s not fussy.
The second gives an estimated height of 80cm and suggests it will survive down to -15 centigrade.
Thirdly it tells us that this is an evergreen fern which is handy as not all fern are evergreen.
Then it goes a bit weird as it tries to explain how to plant your fern, by soaking or drowning? your fern in a bucket before breaking the pot and planting it in a big hole.
Now we have a Nandina label these are often sold in the autumn with bright red foliage and if you look on the back.
The growth rate is very slow, why tells us this? because it is so slow, its worth a mention, so don’t expect it to double in size every year.
Now the important bit, it’s evergreen which is good, looking at the label you might be forgiven for thinking it would be red all year round and it mentions the good autumn colour but not the important fact, that it is green for the spring and summer.
It flowers in June and August, without a description because they are small and insignificant.
Fruits Decorative, they are actually quite colourful red berries, which you should not eat.
Position, Full sun or partial shade, this means it prefers the sun or light shade.
Hardiness, Hardy this means it is European hardy and will be hardy in the UK.
Use plant singly or in groups, this means plant one or if you want a big plant, you need to plant three as one will take too long to grow.
