Tag Archives: raising monarch caterpillars

Keeping our monarchs at home

Joe Pye weed is a handy source of nectar for the monarch butterflies. We have always known Joe Pye as a eupatorium but it has now been renamed Eutrochium purpureum

Joe Pye weed is a handy source of nectar for the monarch butterflies. We have always known Joe Pye as a eupatorium but it has now been renamed Eutrochium purpureum

March is the month when we become aware that the days are shortening and night temperatures cooling but autumn? Not yet, at least not in North Taranaki where we drift ever so slowly from season to season. But every year, the same pressure comes on – the plight of the monarch butterflies.March is the start of the critical period. We have monarchs on the wing twelve months of the year in our garden. To a large extent, that is because we take active steps to guard the late season caterpillars. These are the ones that will chrysalis and hatch out as conditions for them grow more difficult. Given the short life span of a monarch butterfly – usually only a month, the internet tells me – it is these late season candidates which will winter over and guarantee continuance through next summer.

In North America monarchs migrate vast distances to over-winter in the mountains of Mexico but our monarchs are not as determined and will stay at home. Occasionally we find a tree where many are clustered together and it is truly a small wonder in our world to see them stretching and flexing their wings in what little warmth there is on a sunny winter’s morning. More often, we will see raggedy specimens bravely feeding from seasonal plants. The so-called Edgeworthia papyrifera (yellow daphne) can be an astounding sight in August. The key to keeping our monarchs close to home is year-round food supplies, which means plenty of flowers with visible stamens and pollen which are a fair indicator of available nectar.

Swan plants are the food source for monarch caterpillars

Swan plants are the food source for monarch caterpillars

No doubt many readers are currently suffering the seasonal anxiety of stripped swan plants and a surfeit of caterpillars at all stages of development. The caterpillars are very selective about food sources. Basically they need swan plants. We always knew these as Asclepias fruticosa but I see they have now been reclassified as Gomphocarpus fruticosus for the common one and G. physocarpus for the giant swan plant and I can’t commit either of those names to my memory. You can – and we have in the past – get medium and large caterpillars to chrysalis-size on slices of pumpkin but you have to confine them because they will head off looking for their preferred food source given the opportunity. Is there anything as brave as the sight of a procession of monarch caterpillars heading away in search of more food?

Nowadays we try and reserve plants for late season caterpillars, covering them with netting and taking steps to rid them of the nasty yellow aphid that can decimate the plants. There is a specific aphid spray that does not harm the caterpillars when infestations are really bad. Both Yates and Tui have organic products that target mites, whitefly and aphids. Later in the season, Mark will start his chrysalis rescue programme, carefully tying them with cotton to suspend them safely because they can rarely hatch successfully if lying on the ground.

We are working to establish the admirals in the garden, seen here feeding from Lycoris aurea last autumn

We are working to establish the admirals in the garden, seen here feeding from Lycoris aurea last autumn

We are finally getting patches of stinging nettle established. The only reason for this is to encourage the admirals, both red and yellow, to move into our garden. It is not our large native tree nettle – Urtica ferox – but one of the dwarf ones which has turned up which we are allowing to stay. Unlike the monarchs, which are self-introduced to this country and were first recorded around 1840, our brand of red admirals are truly indigenous and not found anywhere else in the world. Because their host plant is not as obliging and hospitable as the monarch’s swan plant, they need all the help we can give them. That said, there was a news item that came through at the start of this year reporting that the US Fish and Wildlife Service is taking steps to protect the monarch butterfly under the Endangered Species Act. Loss of habitat and modern farming methods have caused a massive drop in the monarch population and there are fears that, without intervention, they may die out.

Some utilitarians may ask what useful contribution butterflies make to human life. It is true that there their direct contribution does not equal that of bees. But as gardeners, most of us set out to cultivate transient and ephemeral blooms for no other reason than that they are beautiful and bring delight. Butterflies are beauties of the insect world and their continued presence is a good indicator of a healthy ecosystem.

New Zealand has an active Monarch Butterfly Trust with a comprehensive website. While the obliging monarch is their main focus, they cover the whole range of butterflies found in New Zealand (which is not large by international standards) and they touch on the moths (which are considerably more numerous here but less appealing to most people). You will find answers to many specific problems on that site. While the obliging monarch is their main focus, the site has information on a whole range of butterflies found in New Zealand, which is not large by international standards, and they touch on the moths, which are considerably more numerous here…but perhaps less appealing to most people.

???????????????????????????????First published in March issue of New Zealand Gardener magazine and reprinted here with their permission.

In the Garden: April 30, 2010

• I am reliably informed that the autumn colour in colder inland areas is at its very best. The sudden cooling of temperatures in March followed by a long, dry and calm autumn has resulted in a splendid display. If you are wondering why we never get great autumn colour in coastal areas, it is because we lack the sharp seasonal changes which trigger deciduous trees to colour before dropping.
• Cleaning up fallen leaves and spoiled fruit from under your fruiting trees helps to reduce pests and diseases which can winter over in the debris. This is particularly true with apples and pears. Lay a blanket of compost after the clean-up to suppress weeds and to condition the soils.
• If you are wondering how to prune your raspberry bushes, we will do an Outdoor Classroom on this shortly. While timing is not critical, it is easier to see what you are doing when the leaves have dropped. The rule of thumb is that you remove all fruiting canes from this summer and just keep the new canes.
• Finish the autumn feeding round as soon as possible. While evergreen plants don’t go dormant like deciduous plants, their growth slows right down over winter which slows their ability to take up fertiliser. There is no point in feeding deciduous plants which are dormant or in the process of going dormant.
• Despite being horrified at the price and initially suspicious of an approved organic spray for aphids, Mark was pleasantly surprised to find that Yates’ Nature’s Way did actually work on the swan plants – killed the aphids without affecting the monarch caterpillars at all though it needed repeat applications because it is nowhere near as powerful as the pyrethrum based sprays. On the other hand, the Tui product, Eco-Pest, which is primarily canola oil, had absolutely no effect at all on the aphids when applied at the recommended dosage.
• Most gardeners will be looking at some pretty sad and leafless tomato plants by now. Unblemished tomatoes can be ripened off the vine so harvest these now and keep in an airy, light place to ripen. Gather up all the spent tomato plants and leaves and dispose of them in the rubbish or by hot composting to reduce fungi spores wintering over. I see the advice from Andrew Steens in the Weekend Gardener magazine is to put such diseased foliage on your lawn and then run over it repeatedly with a mulcher mower to chomp it up and leave it to feed the worms in your lawn. This of course assumes that you not one of those ecologically challenged types who kills out the worms in your lawn to preserve a better green sward.
• Some time ago, I wrote a glowing review of The Artful Gardener by Rose Thodey and Gil Hanly. I see it has been reduced from $60 to $25 on special at Touchwood Books (www.touchwoodbooks.co.nz). It was worth its original price, let alone the reduced price.

Monarch caterpillars and butterflies – a mid-life obsession that is safer than a Harley Davidson

The green swan seed pods and the fat monarch caterpillar in high summer

Mark has always loved butterflies. Alas it was his misfortune to be born in a country with remarkably few butterflies so he has had to focus all his efforts on the only obliging candidate, the monarch. When we travel overseas, he likes to be armed with guides to both local birds and butterflies but at home the yellow admiral and the coppers are largely unknown in our area and the cabbage white does not qualify. The red admiral, which is here, is not as much fun because its main host is stinging nettle. New Zealand has an abundance of different moths, many of which are extremely beautifully marked, but you have to be of a nocturnal disposition for these. This brings us back to the monarch which is large, spectacular and can claim indigenous status because it was self introduced (like the wax-eye), arriving here under its own steam, apparently around 1840.

I admit that I fear his dedication to supporting an exponential increase in numbers of monarch butterflies wintering over may be nearing obsessive levels. Even I was a little surprised at the extent of his swan plant plantations. As magnolia crops have been harvested from our open ground area, he has gone in to the cultivated ground with his little seed sower and trundled up and down the rows dispensing swan plant seed. Strung end to end, we are talking several kilometres of swan plants – probably closer to five kilometres than two. What is more, he is successional sowing in the same way he does with the sweet corn and beans. All this is aimed at ensuring that we have plenty of food to take the monarch caterpillars through to late autumn. That way, they are far more likely to winter over here and there are few close up sights of natural beauty as magical as looking up into a tree on a fine winter’s morning and seeing the monarchs waking and stretching in the sunshine.

The drive to have successional crops may strike a chord with many readers who will be struggling now with a surfeit of caterpillars and a dearth of food. There is something both brave and poignant about watching an exodus of monarch caterpillars heading down from a completely stripped swan plant and wriggling off into the wide unknown in search of another. I suspect Mark suffered some emotional traumas in years past, coping with food shortages. One autumn he raised many caterpillars on slices of pumpkin and he finds it hard to cull babies to preserve dwindling food supplies for the more advanced specimens who are likely to reach maturity and chrysalis in time to metamorphose.

Merely sowing swan plant seed is not enough, however. Definitely not. Crops require management. For starters, you want to try and get at least one plant through to its second season so you can gather your own seed. It germinates readily if sown fresh. We have always known the swan plant as an asclepias, Asclepias fruticosa in fact but it has apparently been renamed Gomphocarpus fruticosus which is altogether too difficult for us to remember even with our experience in horticulture. Sometimes it is referred to as milkweed (it exudes a milky sap) but the term swan plant is commonly understood. The seed pod is like a green bubble swan and when it bursts, the fine seeds come out attached to silky white filaments – maybe they resemble white swan feathers? The filaments help the seed to be dispersed by the wind.

The problem with juvenile swan plants is that the monarchs don’t understand about food conservation so you have to protect your swan plants or they will be stripped long before they become established. If you only have a few plants, you can cover them and restrict access to the egg laying butterflies. These days we have so many plants that the supply finally outstripped demand but in the awkward mid stages, Mark did have to resort to a little infanticide to protect the plants for autumn. And we have to be honest and say that our swan plants are not organic. Without intervention in the form of insecticide, the yellow aphids would have destroyed the entire crop before the monarchs even got going. When he first decided that spraying was necessary a couple of years ago, he went through and carefully picked off all the larger grade caterpillars and relocated them to a clean area. These days we just have too many plants so he tries to get his timing right because insecticide is indiscriminate and will kill eggs and caterpillars as well as the nasty aphids. He tries to do it as early in the season as he can before the explosion of monarch caterpillars.

If you only have a few plants or a single plant under siege from caterpillars, it helps to put in a twiggy branch alongside. Too often the caterpillars will chrysalis on the swan plant where they can be very vulnerable to subsequent generations eating off the stem to which they are attached, so it is better that they be encouraged to neutral territory. Our observations are that cocoons must hang in order to allow the butterfly to emerge undamaged. If you have a stray cocoon, you can try tying a piece of fine cotton to its top so you can suspend it. We have resorted to a bit of sticky tape just across the stem at the top of the cocoon which seems to hold them long enough as long as it doesn’t get too wet.

The final piece of the jigsaw for us is having enough food throughout the year to sustain the butterflies. So it is swan plants as host for the eggs and caterpillars and nectar rich flowers for the butterflies. They will just fly away if you live in a green desert with no food for them. I have written before about butterflies feeding in winter on our Prunus Awanui and Edgeworthia papyrifera. There are many flowers with good nectar but I am slightly amused to see zinnias and marigolds making a reappearance here. We haven’t grown these since back in the competitive school garden days of our children but I notice Mark will row them out in the vegetable garden for the prime purpose of feeding the butterflies. In fact the monarchs have caused him to revisit his approach to the vegetable and kitchen gardens and to give space to many flowering plants in order to feed his butterflies. There is nothing as twee as a potager. We are talking more meadow garden style but it is very pretty. The monarchs are a good argument in support of a gardening style which favours flowers twelve months of the year.

Mark is by no means alone in his monarch butterfly fetish. There is a strong organisation in New Zealand to foster the monarch and readers who wish to know more can visit their website on www.monarch.org.nz . This site will also give further suggestions for nectar rich flowers. One of our friendly neighbours has derived much delight from our monarch butterflies visiting his garden in winter, despite Mark threatening to bar code them and charge accordingly. Send our butterflies home, I heard him say. As far is Mark is concerned, his monarch butterflies give him a great deal more pleasure than a mid-life Harley Davidson and are a lot safer and cheaper.

In the garden – 26 February, 2010

The challenge of the ongoing cucumber harvest

  • We have a surplus of cucumbers here. Our formerly well travelled staffer tells us that in Turkey, street stalls sell cucumbers which they peel on the spot, slice in half and sprinkle with salt. The smaller, younger ones are pleasant eaten as a fruit though the Heart Foundation would no doubt prefer the salt omitted. I failed to convert Mark to cucumber juice last year but adding them to unsweetened yoghurt is tasty and ups the quantity consumed.
  • Regrettably we are cooling off somewhat and the days are noticeably shorter. The upside of this is that if you are dying to get into the ornamental garden, you can plant or dig and divide clumping perennials. These are more forgiving than woody trees and shrubs and as long as you water them in well and follow up in a few days time, they should be fine. Most perennials will keep growing until winter arrives so there is plenty of time for them to recover. If you have clumps which have fallen apart and are looking really scraggy, it is likely that they are congested and need to be split up. Make sure you replant in well cultivated soil and preferably add compost.
  • As summer crops are harvested from the vegetable garden, it is time to be sowing and planting winter crops. Pretty well every novice gardener ends up with far too many cabbages, broccoli and cauliflower all maturing at exactly the same time. It is better to sow a few seed every fortnight or so because you want them to mature in stages. If you buy small plants, look out for the punnets of mixed brassicas which are widely available – these usually have two of each vegetable.
  • You can also be planting winter lettuce (which is leafy not hearting), mesclun (which bolts to seed too fast in the heat of summer), Florence fennel (the most versatile of vegetables), spinach, beetroot, parsnip, peas, and carrots. Do leeks from plants now in preference to seed. Mark has just put in his last crop of beans though he is a little worried it may be too late. Don’t delay past this weekend on these in coastal areas. It is too late inland.
  • If you are harvesting rhubarb, make sure you feed and mulch the plant to encourage it to grow again. Rhubarb is deemed a gross feeder, which means it is a hungry plant. Adults may like to try adding grated fresh ginger when stewing their rhubarb. To make it palatable for children, cook it up with a bit of sago (tapioca takes too long to cook) which reduces the sharpness and therefore the amount of sugar you need to add.
  • Further to today’s column, if you have run out of swan plants for your monarch caterpillars, you can finish the larger ones on sliced pumpkin but apparently it is an insufficient food for young ‘uns and leads to deformities. You do have to imprison them in a box with the pumpkin or they will migrate in search of another swan plant, even if there are no more around. You can find more information on www.monarch.org.nz .