Tag Archives: digging and dividing perennials

Tikorangi notes – winter, reversions and grubby knees

IMG_8604‘tis the winter solstice today. This marks the point where the days will start to lengthen again, which is always encouraging. However, it usually marks the point where we descend into the worst of winter weather from here through July. But I tell myself that a winter so brief is not too bad, really.  We are still enjoying plenty of autumn colour – which is more early winter colour here – and more camellias are opening every day. The spring bulbs are pushing through the ground.

Casimiroa edulis

Casimiroa edulis

The absence of any significant frost means the tree dahlias and luculia flower on and we are eating the white sapote crop (Casimiroa edulis). Now there is a taste of the tropics in mid-winter.

IMG_8616I had been meaning to photograph this reversion on a dwarf conifer. Many plant selections, especially amongst the conifer families, are sports or aberrations on a parent plant. Part of plant trialling is to test that sport for stability but even so, you may often see reversions to the original plant. Generally, it is going to be much stronger growing so if you don’t cut it off, over time it will dominate. A quick snip with the secateurs was all that was required on this little dwarf in the sunken garden. The major growth that Mark removed from the top of the variegated conifer in the centre of this photo required a tall ladder, some tree climbing and a pole saw.

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IMG_8619Reversions are also apparent in these perennials. The silver leafed ajuga to the left is showing reversion to plain green. While that particular ajuga is not my favourite (the silver reminds me a bit much of thrip-infested foliage on rhododendrons), it is better than the boring green which barely blooms. I weeded out an ever-growing patch of the plain green. The other little groundcover must have a name but I have no idea what it is. The clean white variegation is sharp and smart but it has a definite inclination to revert to its plain green form, which is much stronger growing. The same rules apply where variegated hostas are reverting to a plain colour. If you want to keep the variegated form, cut out the reversion or you will end up with just plain foliage.

I like the yellow polyanthus with blue corydalis but the polyanthus need relatively frequent lifting and dividing to stay looking good

I like the yellow polyanthus with blue corydalis but the polyanthus need relatively frequent lifting and dividing to stay looking good

I have been much preoccupied with digging and dividing perennials. Still. This may be ongoing but the good news is that the more you dig and divide, the easier it is because the soil doesn’t compact as hard. Over time, I am sure I may cast out some of the plants that need very frequent digging and dividing to stay looking good (particularly polyanthus) but at this stage, I am fine with grubbing about in the garden borders on my hands and knees. Mark laughs at me. Even though I use a kneeling pad, I am a grubby gardener. There are no two ways about that. Mark can come in from the garden, wash his hands and be relatively clean. I come in and have to soak clothes in a bucket of cold water, to loosen the dirt before washing them.

Why so much digging and dividing? Because I am on a steep learning curve with perennials. In the main, I would say that we are pretty knowledgeable about gardening with trees, shrubs and bulbs. But gardening well with perennials is a whole different ball game. I went looking at local gardens a few years ago and it was a revelation to me how badly otherwise-reasonably-competent gardeners managed underplantings. There is so much to learn – not only what perennials like which conditions (that is the easiest bit), but which perennials combine well together, have compatible growth habits and stay looking good over a long period of time. Landscapers usually take the easy path – mass plant a large area with a single variety that will like the conditions. But that is not our style. It is the combinations that make it interesting and take the garden through the seasons.

January 27 this year

January 27 this year

And on June 20

And on June 20

Because we have some big plans for all-new perennial gardens, we have both been turning our attention to learning more about the specific  requirements of many varieties and how best to manage them. This is not a six month project. More like a six year one, at least. But with perennials, the results are quick. I lifted much of the messy swimming pool garden in late January (mid-summer and I didn’t water because there is no tap nearby) and replanted a block with Dietes grandiflora and an ornamental taro. For a while they sat around wilting in the extended autumn heat. But look at it now, in mid-June. The dietes haven’t moved but still have green foliage so they are biding their time for spring. The taro looks great. When a combination works, it is hugely satisfying. When it stays working all year and into the next few years with minimal attention, that is even better.

When perennial plantings work well - Curculigo recurvata with Ligularia reniformis (also in the pool garden)

When perennial plantings work well – Curculigo recurvata with Ligularia reniformis (also in the pool garden)

Garden lore

The more one gardens, the more one learns; and the more one learns, the more one realises how little one knows. I suppose the whole of life is like that

by Vita Sackville-West.
(1892-1962)

Farfugium tussilagineum argenteum - standing up well after being dug and divided last autumn

Farfugium tussilagineum argenteum – standing up well after being dug and divided last autumn

Digging and dividing

While the advice is freely given to dig and divide perennials, it is often the garden task that slips so far down that it falls off the to-do list because it is rarely urgent. If you have clumping, leafy plants which are either dying back in the centre or flopping all over the ground, that is a sign that they will benefit from being lifted, divided into smaller pieces which are then cleaned up and replanted into well dug and composted soil. This patch of Farfugium tussilagineum argenteum (some of you will know it as a ligularia) received this care and attention last autumn and now it is sitting up looking much more attractive, rather than falling apart with leaves lying on the ground.

In our comparatively mild climate, we can do this pretty much any time of the year though hot, dry summer is best avoided unless you water twice a day. In cold climates, plants can rot out if dug and divided when dormant, so times of growth in spring and summer are usually recommended.

First published in the Waikato Times and reprinted here with their permission.

In the garden this fortnight: June 21, 2012

A fortnightly series first published in the Weekend Gardener and reproduced here with their permission.

Before - too much mondo grass, not to mention superfluous hostas and Ligularia reniformis needing attention

Before – too much mondo grass, not to mention superfluous hostas and Ligularia reniformis needing attention

There are times, I admit, when the advice I give as a garden writer is from the do-as-I-say school. Digging and dividing perennials is an example – a recommended activity but not as urgent as other tasks here so rarely gets done. I am reformed, inspired by the dramatic response of plants which I lifted, divided and replanted into well dug soils last year. They romped away. I am working my way through the garden borders, lifting pretty much every perennial (but leaving Helleborus orientalis – the most common hellebore. It doesn’t appreciate being disturbed). As some have been left for well over a decade, it is a major task and takes some physical effort. It also gives the opportunity to clean up the perennial plantings to achieve a more cohesive look. Years of plugging gaps had meant that some were pretty hodge-podge in the selection of plants.

I have carted away two barrowloads of green mondo grass from just one smallish border – too much mondo. A drift of yellow polyanthus will give winter colour, interplanted with bluebells for early spring contrast. The variegated Soloman Seal (Polygonatum multiflorum var.) will give spring and summer detail, all held together by the evergreen tractor seat ligularia (L. reniformis) and the green mondo grass (Ophiopogon japonicus) – but in moderation. All of this is in the lee of a large mandarin tree, which gives wonderful orange winter colour with its abundant fruit. The fun part of gardening is deciding on different combinations for different areas but after the hard work, patience is needed before it all starts growing again.

And after - it needs to grow but it is very tidy

And after – it needs to grow but it is very tidy

TOP TASKS
1) Limit the mondo grass – both the black and green forms. It seems to have quietly spread into too many areas where it is not needed at all.
2) Get a layer of compost mulch onto the borders where I have been working. The compost will feed the plants while stopping dirt splash in rain. It is a fiddly job because it needs to be placed around in each plant by hand.
3) With only two months until spring here, the pressure is on to get winter projects done. This includes my reconstruction of the rose garden. It will make a major mess so once started, it is a case of needing to persevere until it is done. I have not been game to start yet but will run out of time unless I get moving.

Outdoor classroom – rejuvenating tired perennial patches

[1] Many of us have areas of garden which look like this – tired and dull. Although this patch has been kept weed free, mulched and deadheaded, it is many years since it has been actively gardened. There is no alternative to a bit of hard digging.

tired and dull

[2] Dig out all the plants. You can see how heavily compacted the soil has become over many years. It was originally rotary hoed which made it light and fluffy but that was a long time ago.

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Placing the plants on a mat beside where you are working will reduce the mess.

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[3] Dig to at least the depth of the spade and dig again, breaking up any clods of dirt. This incorporates air into the soil and encourages worm activity. Rake the area to an even surface for replanting.

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[4] Different plants divide in different ways so look closely at the plants. The pulmonaria at the top of the photo will pull apart easily to three separate pieces, all with roots and growing crowns. The phlomis at the bottom of the photo could be cut into many plants but I will take this to just two strong plants, reducing each to only one or two growing points.

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[5] If you have dug well, you can replant using just a trowel. Try and avoid planting in rows – staggered drifts look better. I want a quick result so am planting at about 15cm spacings. Take the oldest leaves off the little plant, leaving fresh new growth tips. Remember that the soil is fluffed up and the next rains will compact it a little, so don’t plant at too shallow a depth. Only plant the strongest and the best divisions.

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[6] We give a light feed of an all purpose fertiliser – in this case our locally produced Bioboost – and then mulch. This patch was dug, divided and replanted about three weeks ago and has a mulch of wood chip from our shredder. It should be well established and look lush and vigorous in spring time.

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A step by step guide by Abbie and Mark Jury first published in the Taranaki Daily News and reproduced here with permission.