Gunnera

Have you have ever come across a mature gunnera plant? 

If you have I’m sure it’s something you’ll never forget. From a distance they just look like a clump of rhubarb leaves, but get closer and this herbaceous perennial just seem to grow and grow. Reports of 3 metre high leaves with a 2m leaf span are regularly documented. 

It is one of those architectural plants, like the giant hogweed, whose scale astounded Europeans and made it the must-have ornamental/ edible plant for 19th century horticultural fashionistas and collectors. In Ireland, Kylemore Abbey (Co Galway) and Ilnacullin (Co Cork) planted them up. They were more recently introduced into the Irish gardens but then this triffid-like plant has escaped and naturalised along swathes of Irish coastline as well as along riverbeds, coastal cliffs and forest margins.

The biggest problems are now in particular on Achill Island and in Counties Mayo and Galway where they are classed as an invasive weed

There are two main types of large gunnera. There’s the manicata variety that isn’t invasive and sold in garden centres then there’s the tinctoria which gives us the problems. There are loads of others too down to tiny 10cm high groundcover called monoica but are overshadowed (groan) by their larger cousins.

Gunnera tinctoria produces a large cone-shaped flower head from spring to early summer, with small flowers. The fruit is orange. It is a deciduous plant whose leaves die back in autumn (October) commonly leaving the large brown rhizomes exposed. The flower clusters on the stems occurs early in the spring, with the fruits maturing in late summer/early autumn. Large numbers (up to 250 000 seeds per mature plant) of drupe like, red or orange seeds are produced. Small fragments of the rhizome have the potential to establish new plants.

Growth starts in early spring (March) It can reproduce by both sexual (seed) and asexual (vegetative) means.

Problems caused by Gunnera tinctoria

Due to Gunnera’s wide leaf span, large dense cover can have a dramatic impact on the local biodiversity by light exclusion. On rivers it causes erosion to banks, exposing them to fast running water after die-back in winter. When the plant dies back its dead leaves fall into watercourses and can block drains and watercourses, resulting in flooding. It can also alter the visual aspect of once beautiful landscape vistas, by rapidly colonising large tracts of fallow ground.

While Gunnera has become a major problem in the west of Ireland, INVAS Biosecurity believes in its mission statement of providing the “first line of defence”, and that preventative eradication programs should be put in place now by those stakeholders whose responsibility it is to protect our environment. This would be extremely cost effective both in the short-term, and save millions in the long-term. 

INVAS

Invas Biosecurity, a private company in Dublin are among a growing number of companies that want to control invasive species in the countryside. They can carry out baseline distribution surveys, risk assessments and develop comprehensive management plans, which include spraying, Rhizome injection, Cut and paint herbicide injections in much the same way Japanese Knotweed is controlled. Biodiversity Ireland would also like you to report any sightings of the plant if you see them in the countryside (not in your neighbours garden I don’t think).

Care for gunnera in your garden

Larger gardens can showcase the gunnera manicata and keep it under control without issues. One thing that stops the plant in its tracks are temperatures lower than -8°C, so a good hard frost will kill them off unless they are well wrapped up with dead leaves. If you have a smaller variety in the garden you will probably cover the crowns with dry mulch. The leaves of larger varieties could be cut off after the first hard frost. Inverted, the leaves provide excellent coverage for the resting crowns.

Another method to help keep out moisture is to remove leaves after the frost, cover the crown with  60cm of straw, cover with a burlap tarp, or large plastic container, such as a tub, and then add another 60cm of straw. Seasoned wood chips or sawdust will work even better. After all danger of a hard freeze is gone, in late March or early April, protection can be removed. 

Just to say again, it’s reckoned that G. manicata – the Chilean one – doesn't share its Brazilian cousin's invasive nature. So perhaps this should be your preferred Gunnera should you have the time and space to grow one.

Shoo Fly

There are many types of flies around at this time of year.  A few do a bit of pollinating but most of them are just a nuisance.

The two types we see more often are houseflies and bluebottles, which love to be around humans. You’ve probably got one flying overhead right now or bashing its head against the window. Although similar in many ways, there are some differences between a housefly and bluebottle, which may be important when it comes to dealing with the problems they cause.

Humans have pretty much sought to keep houseflies out of their lives as long as they've had houses for them to fly into. Even before advances in science allowed them to understand the risk of infectious disease, many people saw the fly as a harbinger of sickness and death. Some ancient civilizations made regular sacrifices to their respective fly gods to keep the swarms out of their homes and temples; we generally just get out the rolled newspaper. 

Houseflies lay their eggs in moist, decaying matter especially household waste, manure or compost – unlike bluebottles which exclusively lay on dead animal bodies, meat or cheese. 

Under ideal conditions the whole lifecycle – from egg to maggot to adult – can take place in less than a fortnight. As adults, houseflies can fly distances of five miles or more, so they have little difficulty travelling from these breeding sites, entering your home and landing on the cheese sandwich you have just made. Houseflies stay more local and don’t go more than a few hundred yards in their 10-20 days of life.

Houseflies have a series of stripes along their mid-section, while bluebottles are a distinctive metallic blue. The larvae are almost indistinguishable except for size, the full-grown bluebottle maggot being larger but it’s hard to compare really.

Houseflies are the flies with the erratic flight patterns, usually around lampshades. Both houseflies and bluebottles can seemingly come in the house though the smallest of cracks (But can’t get back out of them)

If you have a lot in the house with the windows closed, you might have something dead under the floorboards. 

It’s not all bad

You would think their only purpose was to wind us up and spread disease (there are a lot) but they do have a use in the food chain, they fulfil an important environmental role as scavengers. As houseflies and their larvae feed, they consume nutrients in rotting organic matter. They leave behind picked-over remains that other organisms, bacteria and enzymes can further break down.

Bluebottle maggots are sometimes used to clean wounds. These larvae were reared at a Chinese housefly farm, where experts believe they may be used to develop cancer medication.

Flies and their larvae are also an important food source for a large number of predators. Housefly pupae contain large amounts of protein and are thus especially beneficial to the various birds, reptiles, and insects that prey on them. You can even purchase frozen or freeze-dried housefly pupae to feed pet spiders. It’s still not enough to stop getting the swatter out though. 

Dealing with Fly Problems

My mother used to keep everything closed in the house when the flies were around. They still got in as people came through the door. I’ve compiled a few tips here and I can say with confidence that none of them really work for long.  

Cover your food and keep the kitchen tidy. Good hygiene and a few sensible precautions, such as frequent cleaning of the kitchen drains, disposing of scraps carefully and keeping waste and compost in secure bins, form the best approach to controlling fly problems in the long term.

There are some high tech methods you can use. UV fly zappers work well and larger buildings have air barriers where the constant flow of air outwards buffers the flies so they don’t come in.

The simplest example of this would be killing flies with a swatter. You can get electrical one with a small charge in them and look like a tennis racket. 

 Fly paper is something I tried to use in my polytunnel one year but I kept getting entangled in the sticky tape. You can use them around the rim of a hat which might work. 

The team of gardeners at Glenveigh walk around with tins of smouldering turf on them which is fine outdoors but not so practical in the house. You can get sprays but you’ll need to check if they are safe to use in the kitchen.

Maybe try natural methods.  There are plants and essential oils you can put near windows and doors. Ginger, basil, pepper, eucalyptus, geranium, tea tree even catnip lemon and cider vinegar are all said to work for a while.

If all else fails, get the vacuum out,

Plants that Move

 My 'Little Tree Plant'

Plants are moving all the time. Most move so slowly that we can’t see it, unless the wind is blowing or we brush past them. 

Many plants also have leaves that move on their own. Leaves will turn to face the direction of the sun, which is a slow gradual process. Some plants move for different reasons like distracting animals that might want a nibble.

A lot plants have leaves that curl up or roll down under stressful conditions like drought or cold, but recover afterwards. Hardy rhododendrons lose most of their moisture and both curl and hang limply all winter, yet recover fully when spring returns. It’s thought this habit helps keep frost crystals from forming and damaging leaf cells.

I had a prayer plant (maranta) which used to fold its leaves up at night, which I found fascinating. This effect is something called nyctinasty which is common in some plant families, such as the legume and oxalis family. Even the clover in your lawn does the same thing.

The movement is caused by a hinge-like structure at the base of the leaf or leaflet called the pulvinus that is filled with water during the day, but drains at night, so that the resulting lack of turgor (pressure in the cells) causes the leaf to fold.

Reacting to Touch

This brings me to my latest shopping purchase. I have bought two types of plants that have moving leaves, but this time, when they are touched their leaves fold up and collapse. I have bought some Mimosa pudica seeds to grow on and three ‘Little Tree plants’ (Biophytum sensitivum)

The phenomenon of plants that react to touch is known as thigmonasty or seismonasty, and occurs when something touches or shakes the leaf. And some will also react when you hold a match up to them. This is usually rapid and is certainly visible. 

Touch Me Not

The Mimosa pudica is a legume and also known as sleepy plant, touch-me-not or shy plant. They are short-lived houseplants and can be a weed in tropical countries where they originated. A light touch causes a single leaflet of the leaf to fold inward, a firmer touch will lead to the whole leaf drooping and shaking the plant will cause all its leaves to collapse. If you run a finger down the leaf, the leaflets will close like dominoes. They are easy to grow from seed so I’m having a go myself.

Little Tree Plant

Less well known is the little tree plant (Biophytum sensitivum), a small herbaceous houseplant that looks like a tiny palm tree and is sometimes used as a tree substitute in terrariums and fairy gardens. It is modestly touch sensitive, but its leaves move all on their own much of the time, albeit quite slowly. I couldn’t find the seeds so ended up buying three plants from an orchid grower in the Netherlands.

The plant originates from India and South Africa, where it can be found growing in wet, boggy soils near streams and waterfalls, where it is shaded by taller trees and shrubs. I thought it would live quite happily in the bathroom. The plant seeds are over a Euro each to buy so I will be collecting my own from these mature plants. The star shaped pods formed after flowering explode and can scatter the seed over a metre so I will need to either cover the plant with a fine mesh (think sandwich cover on a picnic) or encase the pods in plastic bags to collect the seed, there are a lot of flowers on the plant so even if I have to get the dustpan and brush out I’ll be sure of getting some to grow on.

The leaves of the little tree plant fold downwards and the stems rise at night. It’s said the plants produce many healing compounds and are widely used in Indian, traditional and Western medicine. They are usually grown as annuals.

Insectivorous plants

The other group that includes plants sensitive to touch are carnivorous plants or, more correctly, insectivorous plants.

The best known of these is the Venus flytrap (Dionaea muscipula), often offered as a houseplant, although rarely very long-lived in the average home environment. I’ve tried to grow these before but find they rot easily. It might be the house conditions or the fact that I keep prodding the fine hairs in the trap with a pencil to see it closes up. 

My resurrection fern (Pleopeltis polypodioides) is the hardiest sensitive plant I ever owned. It survived without a drop of water all scrunched up for years in a drawer, I watered the apparently dead fronds and they became completely green and opened up within a day after a good soaking.

Peonies and Cuckoo Spit...

 Paeonia lactiflora

I pass a garden full of peonies on my way to the shops.  Most of the year my eyes would be fixed on the pavement, the road or phone depending on traffic conditions, but in these few short weeks the beautiful display of large pink and cream flowers shout at me from over their garden wall.

These particular plants are called Paeonia lactiflora ‘Bowl of Beauty’ and fall into the category of herbaceous peony. These are the most well-known type of peony. They are disease resistant perennial plants that enhance the structure and beauty of any garden and produce some of the best cut flowers available. They bloom during the transition from spring into summer, with each individual cultivar blooming only around 7-10 days. The foliage of shining green leaves remains throughout the summer, dies back to the ground in winter and re-emerges early each spring.

Herbaceous peonies require very little care and live for generations. 

There are other less known type of peonies.

We have the Tree Peonies, which are woody perennial shrubs.

Woodland Herbaceous Peonies that are worth noting individually due to their preference for shade. Intersectional Peonies, also known as Itoh which are a hybrid created by crossing a tree peony with an herbaceous peony and are quite rare. There are also peonies that grow well in containers called Patio peonies.

You can buy the plants now from garden centres and it’s a good time to see the real flowers and if they appeal to you, alternatively you can buy bare-rooted plants in autumn. They do need quite a bit of space to flourish, enjoy full sun and mulch in spring.  They can be propagated by division too in autumn which also helps to rejuvenate the parent plant.

Cuckoo spit (spittlebugs)

Gardeners are being urged to report sightings of spittle on their plants in a bid to stop the insects inside spreading a deadly disease through the UK and Ireland.  

The disease is called Xylella fastidiosa bacteria, which prevents water travelling from roots to leaves. It can cause symptoms including leaf scorch, wilt, dieback and plant death. The disease is spread by insects that feed on the xylem of plants. This includes froghoppers which live in the spittle.

While the disease has not yet been spotted here, it has already taken hold in France, Spain and Italy, where it has killed millions of olive trees.

Cuckoo spit which surrounds the insect begins to appear in late spring at a time when the familiar call of cuckoos can be heard, but otherwise has no connection with the bird.

If Xylella is discovered, all host plants within 100 metres would need to be destroyed. The RHS (Royal Horticultural Society) also say there would also be an immediate restriction of movement for some plants within a five kilometre radius, so it’s being taken pretty seriously.

More than 500 plants are at risk, including lavender, oleander, rose, rosemary, chrysanthemum, dahlia, fuchsia, willow and flowering cherry.

Any sightings can be reported online at xylem feeding insects.co.uk who will redirect you to the survey. The survey will help to gather data to inform a response should Xylella reach the UK.

Spittlebugs are not a pest, so please don't remove them, but they are an innocent carrier of Xylella.

Biology

This froth has no connection with cuckoos

It is secreted by the immature stages of sap-sucking insects known as froghoppers, presumably as a means of protecting themselves against predators

The adult insects are present during mid-late summer and live openly on  plants. They do not produce cuckoo spit or cause any noticeable damage

Overwintering eggs are deposited in plant stems in late summer.

Can be found in UK gardens, meadows, grasslands and woodlands from April to late June

The most common species here is the meadow spittlebug (Philaenus spumarius). Adults are 0.5cm long and vary in pattern and colour from pale brown to black and can jump many times their body length

The red-and-black spittlebug hatches out on the roots of plants, rather than in blobs of spittle on plant stems

There are ten species of spittlebug in the UK and Ireland and the young - called nymphs - all produce whitish, frothy blobs of spittle on leaves and branches.

Control

• Apart from producing the 'spit' these insects have little detrimental effect on plants.
• If considered unsightly, they can be wiped off by hand or dislodged with a jet of water from a garden hose.
• There is no need to use an insecticide against froghoppers.