Fewer than half know that daffodil bulbs are planted in autumn so they can flower in spring. Picture: AP

London - Our knowledge of plants seems to have taken a harsh pruning.

Half of adults cannot name a single shrub, while four in ten are unable to recall a household plant, according to a survey.

Meanwhile more than a quarter do not know that a pumpkin grows above the ground, and fewer than half know that daffodil bulbs are planted in autumn so they can flower in spring.

The poll of 2 004 adults – on behalf of the Royal Horticultural Society – also found that a fifth do not grow any plants themselves, with many blaming a lack of time for not getting out in the garden.

Young people aged between 16 and 24 were the worst performers on a number of questions. About 66 percent of this group did not know the name of any shrubs. They are also the least likely age group to ask for advice on gardening, with just 54 percent willing to seek help compared with 64 percent of all adults.

Grandparents emerged as being the most likely to encourage young people to start gardening, with parents also having an influence. The survey also found that very few people who grow plants would describe themselves as a "gardener", and that many consider the term "too serious".

More than a quarter of people who grow plants outside said they would not describe themselves as a gardener, and just three percent describe themselves as experts. 

While the survey revealed some gaping holes in our knowledge, there were also positive findings.

Although naming shrubs and house plants proved too difficult for many, 70 percent of respondents correctly answered that annual plants grow, flower, produce seeds and die in one year.

Nine in ten of those questioned also had enough outdoor space to grow things such as flowers, fruit or vegetables.