advice on repotting dawn redwood please

[peterb]

Hi All
Now before i'm crucified , i know it's not the right time of the year and no i'm not intending to repot now. What i'm wanting is advice for when is the best time autumn , spring or when , can i bare root seeing as it is a deciduous tree , how much root can one cut and does one need to prune back the top when one cuts root. The reason i'm asking is i have one in a nursery pot while i try to thicken the trunk, but it's struggling in the adelaide summer and i don't think the soil is moisture retentive enough so i want to repot but thought if i'm repotting i would like to work on the roots and spread them out etc thanks in advance for any info
kind regards
peterb

[shibui]

To get it through summer you could sit the pot on top of another larger pot filled with potting mix or a bucket full of gravel (bucket will hold water). Maybe just sit the pot directly on damp ground. Let the roots grow out through the drain holes of your current pot and into the pot below. That will give it far greater root run as well as more moisture so it will grow more. You can sort the roots out when you do a full repot. At worst sit the pot in a shallow tray of water in hot weather. They seem quite tolerant of wet roots.

I generally repot my dawn redwoods in spring but that is just habit. I have not tried any other time of year so cannot recommend.
I am in the habit of pruning the top back when I remove roots but I have heard reliable growers say it is not necessary. Have only tried it once without any problem. Usually you will want to prune the top anyway to correct direction, improve taper, etc - even if I want it to grow more I still find it better to keep some control over the shape - the more leaders you have the smaller each individual pruning cut will be when you eventually cut back and the better will be taper.

[peterb]

Hi Shibui
Thanks for the tips , i put it into a tray with some water yesterday to try get it through the next few days of mid thirties . I'm going to do as you suggested with the bigger pot of potting mix under . At the moment the base is +- 25mm and it's about 1.5m tall , should i start the taper chops now or let it grow on a season or 2. Do you bare root when you sort the roots out or do you treat it like other conifers . thanks for the advice
regards
peterb

[shibui]

I would advise starting taper chops early. You may lose a little diameter growth but that will be more than compensated by better eventual shape I think. After pruning allow several new leaders to develop and grow. Eventually remove most to leave just the best line and taper. That way you end up with several small wounds that heal quicker rather than a single large one. Nothing worse than a really thick stump with a huge scar and miserable thin new leader developing In my experience (mostly tridents) it also takes far longer to grow the new leader to match the stump than if you develop a trunk with multiple leaders and then prune them back.

No problem bare rooting Dawn redwood (I regularly bare root pines as well - doesn't seem to worry them here)

Just bury the existing pot a few cm into the new box of potting mix so there is good contact between the new mix and the roots already in the existing pot. Then see how it goes. Might still want to sit the new pot in water if your tree is still struggling and we get more hotter weather.