Zombies, earthstars and other 'alien' invasions to look out for in your garden

Geastrum triplex (earthstars)
Geastrum triplex (earthstars)

Found some strange plants or insects in your garden this autumn? Could these odd invaders be one of them?

From 'alien' fungi and zombie bees to frightening-looking foods, the Royal Horticultural Society is aware of some more unusual finds you may come across if you're foraging in gardens and woods this autumn. Here's what to look out for...

Moth pupa

Moth pupa

1. Sweetcorn smut

Sweetcorn will have a rude awakening if smut invades. Smuts are fungal diseases that can affect leaves, stems, flowers and sometimes storage organs, such as bulbs and corms. In the case of sweetcorn, affected plants are often stunted and distorted and feature grey and swollen kernels that burst to release huge numbers of black spores. Although considered a delicacy in some countries, including Mexico, in most cases affected plants should be destroyed and the soil rested from that particular plant type for several years. Resistant cultivars are also available to keep sweetcorn fans happy.

2. Weird pods

Dramatic pods resembling exotic-looking cones that open to reveal blood-red berries are actually sheltering magnolia seeds. Bursting months after the lovely bowl-shaped white, pink, red, purple or yellow flowers, gardeners can be startled to find these sinister 'growths' on their beloved magnolia trees and bushes at leaf fall.

Kippered carrots

Kippered carrots

3. Earthstars (Geastrum triplex)

Kicking up leaves this autumn? You might find these strange flower-like fungi which grow on dead organic matter, and are often found in the leaf litter beneath conifers and deciduous trees. These fascinating fruiting bodies emerge during autumn when their bulbous outer casing folds out like the petals of a flower, creating a star effect.

There are 18 species of earthstars in the UK, with the collared earthstar the most common and bearing a distinctive crack near its centre, which gives the appearance of a collar around the spore sac. When rain or wind disturbs the earthstar, spores are released through an opening at the top.

4. Wriggling pupa

A bee burrow

A bee burrow

Pupa is the stage between the larva and adult of many insects. Some species of moth pupa are often found in soil when tidying up the garden. These brown cylinders, from 1cm to over 2cm in length, pointed at one end and ribbed, can wriggle when touched.

They will emerge as adult moths come spring. Either return them to the soil or place them in soil in a jar to observe the moths. While the caterpillars can cause some damage to plants, moths are important pollinators and caterpillars are food for birds and other wildlife.

5. Zombie bumblebees

It is common for only bumblebee queens to survive the winter. To do this they seek a sheltered place and enter a state of torpor to survive the winter months, avoiding predation, starvation and disease. Typically the queens bury themselves in well-drained soil on north facing banks, reducing the likelihood of winter sun warming the soil and waking them up. In gardens, compost heaps and potted plants can meet these requirements.

Sweetcorn smut

Sweetcorn smut

Inevitably, gardeners sometimes disturb overwintering queens. If this happens and the bee remains docile, loosely cover her up again, so she can dig her way out in the spring. If the bee is very active help her on her way by feeding her a sugar solution.

6. Kippered carrots

Some pretty strange-shaped root veg come out of the ground at this time of year. Indeed, carrots can appear to have fangs, be split, curled, inter-twined or best of all 'kippered' - opened out and flattened like a kipper.

Much damage, especially kippering, is down to a virus infection, but other distortion is due to damage to the tender tip of the young root because of contact with stones, damage from hoeing or weeding, or by microscopic worms called root-knot nematodes (there are many forms of nematode). Weird carrots, although unsightly to some, can of course still be eaten.