Tag Archives: Phlomis russeliana

When good plants go rogue

I liked how the cutwork foliage provided a contrast to the dominant grassy foliage

It is no good. The plume poppy had to go from the sunny Court Garden. While I liked the foliage contrast, it is just waaaay too invasive to leave in place.

That is the full extent of the flowers. Pinky beige, perhaps?

The plume poppy is Macleaya cordata, native to China and Japan. It has an attractive blue-grey leaf that looks a bit like the plant version of cut-work embroidery. In spring and summer it shoots up stems to maybe two metres before flowering. True, the flowers are not exciting. More brown than gold, they look like seed heads even when they are in full bloom but they have a certain feathery charm while playing second fiddle to the more striking foliage. The problem is that it runs below ground, more like sprinting than running in some situations.

Here a fortnight ago, gone today on the grounds of bad behaviour

We have grown it for years in the high shade of the Avenue Gardens where it has not been problematic. The running tendency slows in shade – more a walking pace  – and in the thinner, dry soils it is easy to pull out wayward shoots and keep it to an area. I was not prepared for what it would do in cultivated soils in full sun. Not only did the runners bed down to a greater depth but they headed off with gusto in every direction, popping up metres away from the original plant.

Making a break for it

Really, it was the determination to colonise the paths that sealed the fate of this plant. Look at these runners appearing in the terrace. Not only have the shoots struck out enthusiastically on every side, this terrace is 30 cm higher than the garden bed, separated by a brick wall. I just don’t need a plant that can make such determined efforts to colonise. It was already growing through other perennials in the garden beds and leaping beyond.

It is going to take me a few years to completely eradicate it because roots that remain below ground will continue to push up growing shoots but I removed all that was visible two weeks ago and will just keep on its case until it finally disappears.

Macleaya cordata can remain quietly co-existing in the high shade of the Avenue Gardens

It can stay in the shade of the Avenue Gardens but I can’t be having invasive thugs in the Summer Gardens.

Phlomis russeliana flowering now in the shady Avenue Gardens where it will probably be fine left to its own devices for another decade or so.

Another plant that has surprised me with its vigour is Phlomis russeliana or Jersualem sage. While described as a perennial for sunny spots, we have long used it as a low maintenance, obliging bedding plant in the high shade of the Avenue Gardens. It has never needed any attention there, bar cutting the tall growth and spent seed heads back to the ground at some stage in winter. The only time I have ever done any work on lifting and dividing it was when I raided the patch to get plants for the new, herbaceous borders.

In the sunshine, the phlomis romps away and needs major attention every two years at least.

Introduced to the bright light of full sun and well-cultivated soils, the phlomis has become something of a triffid. The growth is lusher and much stronger. The twin borders are only entering their fifth summer but the blocks of phlomis have already been lifted and divided twice, discarding probably half of them in the process. I think I can get away with a total dig, divide and replant every second year if I alternate it with picking and thinning them from the top in the year between. It is a bit more work than I had anticipated for a cheerful but utility plant.  While it seeds a bit more in sunny conditions, at least it doesn’t spread below ground like the plume poppy.

The lines between a strong grower, a thug and an invasive weed are sometimes finer than we expect. Generally, we will cope with the first and get rid of those in the second two classes.

Thugs in the garden

I am surprised by how strongly Iris sibirica grows in well cutivated soils and full sun. I have moved the discoloured Xeronema callistemon behind the iris to the right to a more protected position 

Thugs. Not trugs.

We are cautious here. We do not want to unleash plants that threaten to become weeds and therefore become maintenance nightmares. Some plants that set seed rather too freely (like Orlaya grandiflora, Verbena bonariensis and the perennial forget-me-not, Myosotis scorpioides) fall into this category, but they are easy to pull out if they are seeding in the wrong places. Other plants are far more difficult because they wriggle their roots below ground to entwine anything in their way – not unlike couch grass but considerably more decorative. The pretty, blue Salvia uliginosa and Japanese anemones are examples. These are the plants that we are really cautious about placing and controlling.

And then there are the thugs that stand four square and strong and will swamp anything in their way. Thugs need space of their own. Preferably permanent space because some of those thugs can get too large to handle easily in a short space of time. Learning to garden with sunny perennials is teaching me quite a bit about thugs.

Chionochloa rubra, not a thug but seen to best advantage when allowed to stand in its own space

When I planted up the new Court Garden a few weeks ago, I removed such thugs from the herbaceous borders to relocate in the bigger space of the new garden. They are all good plants but way too strong for the congeniality of an herbaceous border. Calamagrostris ‘Karl Foerster’, Elegia capensis and the large growing salvias were the main thugs that I had used extensively. I also relocated all the Chionochloa rubra, not because it is a thug but because it needed more space to allow it to star in its graceful glory. And Stipa gigantea because it was underperforming in the herbaceous borders and I thought it might be better en masse in its own space.

Raiding the borders left some big gaps, and indeed some large holes. No problem, I thought. I had additional top soil to fill the holes and plenty of plant material to fill the spaces and it seemed a good opportunity to tweak a few areas in the borders which I felt were a bit messy – more messy-matrix than dramatic swathes of plants. I figured all I had to do was to consolidate the areas where I had tried to fill in spaces with additional material. A bit of fine-tuning.

I am sure most gardeners will understand that situation where what we think will be a relatively small project escalates into a major operation. This is one of that ilk. For I found the second tier thugs. These plants have only been in two and a half years and for the first two years, I was simply delighted at the quick result achieved in these borders started from scratch. Gardening with sunny perennials was a completely new experience and so rewarding. Yes, well….

Phlomis russeliana to the left, Elegia capensis to the right with Lomandra ‘Tanika’ in the middle

I am now looking in askance at some of the plant selections. Great plants, but they are going to take a bit more work to keep them that way than I had anticipated because, boy, are they strong growers in this situation. Phlomis russeliana – Turkish sage – with its attractive, tiered yellow flower spikes, has quietly flowered away in our woodland without problems for decades. Moved into full sun and well cultivated soil, it has formed massive underground root systems and overgrown tops in a very short space of time. Iris sibirica – wow. Admittedly, I planted large chunks of it in the first place rather than separating the rhizomes and in springtime, it is simply glorious – so much so that I wanted to add new varieties and colours. Hmmm. All that foliage flops over in autumn, smothering nearby plants and it has to be cut back eventually because it doesn’t even pull off easily. I thought it would be a good time to dig and divide them. It took all my strength to get these plants out of the ground and I ended up with mountains of them. I replanted them as individual rhizomes and mulched with compost. In replanting the same area, I ended up scrapping at least two thirds of them as surplus. And each patch of maybe three or four square metres takes about a day and half to do. I have done four blocks, I have two left to do and I got rid of the seventh block entirely. That is a lot of labour input and time to just one plant type.

And the lomandras. These are tidy, Australian evergreen grasses. We only have two different ones and probably started with a single specimen of each because Mark never buys the same plant in multiples. They kicked around the old nursery area for years, unloved, uncared for, waiting for someone to find them a forever home. That should be a clue as to how tough they are.

The compact dark green lomandra (with freshly divided phlomis to the left). It will be a named clone; it is just that we lost the name

The compact, forest green variety (name has been lost in the mists of time) is very good. And very well behaved. The very dark green colour contrasts well with everything, really. I wouldn’t mind it growing a little taller in this situation – it is only knee high – but it is very tidy. Not a wow sort of plant but excellent in the chorus line of back up vocals.

Too much Lomandra ‘Tanika’

The other one we have is Lomandra ‘Tanika’ which is widely marketed in this country. It is larger growing, sort of anonymous mid-green and what is called a reliable performer. It is one of those bullet-proof plants where you start, as we did, with one, put it in good conditions and next thing you know, you have eleventy thousand of it if you want to divide it. Enough to fill a traffic island or a motorway siding, even. It looks attractive in form for the first couple of years but if you don’t lift and divide it, it threatens to become an overgrown, overblown thug.

The autumn hues of our native Anemanthele lessoniana – also evergreen

I can’t get too excited about the lomandras. While they can be tidy plants, they lack the flower power of showier grasses and they are bit, well, utility. Space fillers. Evergreen and they stay looking the same all year round, which, I admit, some people see as a desirable trait. I am scaling back ‘Tanika’ – composting about 80% of it. It has another two years to win me over but at this stage, I think I would prefer to replace it with our native Anemanthele lessoniana which fills a similar niche but with more foliar interest and lower maintenance requirements.

What I thought would take maybe four or five days’ work – filling the gaps in the herbaceous borders created by my earlier raid – has turned into several weeks. I am quite happy doing this because it is an active learning exercise but I don’t think I want to be doing it as routine maintenance.

The lesson is that there is no substitute for trialling plants in situ and making some major calls when it comes to swapping some selections out for others.  It is why other people’s plant lists are a guide, not a manual, especially if they are overseas recommendations. There is fine line between plants that are sufficiently strong growing to hold their own in herbaceous plantings and plants that are too strong to grow in happy congeniality.

Oh, and give plant thugs the space they need or don’t use them at all. Otherwise they will swamp out other plants of a more refined disposition.

At least the Iris sibirica star in spring, even if they are going to take ongoing work to keep them from smothering their neighbours