Well, mine finally died and so far no new shoots but the good news is I have just received delivery of two plants. I'm going to keep one in a pot and try again with one in the ground - see if I can do any better this time round. Last time I seemed to follow all the rules and it still died Hope these last a bit longer.
How did everyone elses do over the Winter, many survive?
Di
I'm at an age where my back goes out more than I do.
Supporter of the N.A.S.
These that came recently were potted in ordinary multi purpose, and are really pot bound but look to be thriving. The one I'm going to keep in a pot I shall probably try with a bit more MP into the mix than I usually use and see how it goes. The one I'm going to plant out will have to take it's chances. I'll plant it in the same spot as my old one where, in theory, the soil should be okay, and keep well watered, but somehow I still feel trouble brewing. Shall you try again Dave?
Di
I'm at an age where my back goes out more than I do.
Supporter of the N.A.S.
I've just been looking at my indivisa, which prompts me to resurrect this thread. It is the last of my most 'recent' sowing of this species, the others having been given away over the years or killed in the interests of continuing research! Until recently, it has spent the last 5 of its 11 year life cramped into a 20L pot. During this time it has been baked dust dry, become thoroughly waterlogged and during the past winter, frozen solid at the root. Understandably, leaf size has suffered and I realised during spring that it would need to be either planted out or potted on.
There really isn't enough room for an indivisa to develop properly in the borders here and in any case, it is definitely one of the plants I'd like to take with me should I move in the next few years. During May, I knocked it out of its pot to see what if any root growth there was. Happily, lots of thick white roots were running down the outside of the root-ball indicating that below soil level at least, everything was fine. Above soil level, the crown had half a dozen metre long, yellowing leaves from a couple of years ago and much shorter younger leaves from last year all on top of a woody, slightly gnarled, 40cm trunk.
Time seems to fly for me and it wasn't until 4 weeks ago that I got around to potting it on. I chose a deep, 50L 'tree pot' and made up a very sharply drained compost of ericaceous mix, sterilised loam and grit ... lots of grit - around 30-40% of the total volume. To this, I added a small amount of osmocote slow release granules and then potted the Cordyline with at least 10cms of its trunk buried in the compost. This follows my practice of always potting Cordyline indivisa deeply because it appears to be one of those species that needs to produce and be sustained by fresh, adventitious roots throughout its early life at least.
From pics of plants in the wild, the healthiest colonies appear to be those that grow in scrub and open woodland where there would be a regular replenishment of leaf litter and detritus. Indivisa's tendency to 'wobble' at stages in its life cycle suggests to me that it is adapted to produce new roots to take advantage of this build-up of humus provided by neighbouring trees, shrubs and soft plants. Effectively it 'stem roots' and grows up with the increasing humus layers. This needs to be addressed rather than looked upon as a potential problem. I've grown enough from seed over the years and killed plenty in the process, but am now fairly sure I've got at least part of the 'handle' on what needs to be done.
When grown from seed, most plants develop this wobble within 12-15 months and if provided with extra compost around their bases at that stage, rapidly root into it with the original 'seedling' roots quickly dying away. Seedlings will grow on until they stall again at the next 'wobbling point'. If they are simply allowed to continue wobbling, they go into decline because the original, basal roots are naturally short lived. 'Stem rooting' seems to be the norm with this species, although I suspect that once a decent trunk has formed with at least some of it now below soil level, the need for regular increments of compost around the base of the plant becomes less imperative.
Back to mine. 4 weeks is not a lot of time to see improvements in Cordyline indivisa, but it is starting to grow away strongly again. The old metre-long leaves died away quickly and the crown is pushing out lots of new leaves already. Too early yet to poke around in the compost, but I'm fairly sure that there's a lot of increased activity down under as well. I'm of the opinion that this species is all about the state of its roots. If these are plentiful, young and healthy, the plant is less cold sensitive than C. australis, drought tolerant and indifferent to sun or shade, although it does appear to do best in sun here in the UK. My findings are that it prefers a slightly acidic soil and seems to grow better where there is plenty of air movement. Perfect drainage is essential and were I to plant a new one out, I would definitely keep it potted until it starts to form a trunk.
I agree with most of what you say Dave, but when you say the they naturally lose their roots, how do you know that, or is it your observation of your plants. Not saying you are wrong as I don't know, but to me it may not be that they naturally lose their roots, but that we have not given it a compost it is totally happy with yet
I think the answer may be oxygen in the soil, and if/when the soil becomes compacted the roots start to die off. If you heap an open mix compost up against the trunk it gives the plant what it likes... plenty of air, but once that compacts down you have to repeat the mounding up. I'm sure that does not happen in the wild to the extent we may need to do it.
Mine was ok for about 18 months then became rocky in the autumn as the roots had rotted. I mounded up with a gravel/peat mix and over winter it rooted well, becoming firm. The next autumn it became rocky again again I mounded up and it firmed up over winter. On the third autumn of rocking I removed it from it's pot and removed the compost..... all roots had rotted except those next to the plastic pot wall on the sunny side of the pot. I concluded that the heat from the sun was drying out the compost on the sunny side allowing a gap and air to penetrate. All roots in the compacted compost remained too damp with not enough oxygen, and rotted.
My overall theory is that the compost we use gradually rots down allowing compaction, and a lack of oxygen results. Bodster has one growing well by the sound of it due to planting on the site of an old conifer. This gives a very coarse fibrous soil. When I get another I shall try planting in composted pine/conifer needles and eucaluptus leaves with grit
Dave Brown wrote:I agree with most of what you say Dave, but when you say the they naturally lose their roots, how do you know that, or is it your observation of your plants. Not saying you are wrong as I don't know, but to me it may not be that they naturally lose their roots, but that we have not given it a compost it is totally happy with yet
From my observations of quite a considerable number of seedlings over the years have been that original roots are significantly thinner and weaker than the adventitious roots that develop later. I can't think that compaction of compost and/or subsequent lack of oxygen to the roots would be the case since I've always used a very high proportion of perlite in the compost for the first few years. When shaking compost away from the roots of 3 year seedlings, the 'seed roots' are very poor and sparse in comparison to the adventitious roots, which were strong and numerous. I've also 'cleaned' off compost from two 5 year old plants and by then all roots were adventitious.
I should add that I've not experienced any problems with growing indivisa in pots so I think that the compost 'ingredients' as well as the structure is about right. I don't deny that it's a tricky sod when planted out because you need to make sure there's very high porosity in the planting site. I'm not convinced about it needing lots of water - I've dried quite a few out and never killed one as a result. That is not to say it should be kept on the dry side, just that I'm not convinced evenly moist conditions at all times are essential for its survival.
but the good news is I have just received delivery of two plants. I'm going to keep one in a pot and try again with one in the ground - see if I can do any better this time round. Last time I seemed to follow all the rules and it still died 
Hope these last a bit longer. 
