Chinese Elm - Yellowing of leaves

[HK90]

Hi

Please lend me some wisdom– I’m a newbie to bonsai care!!
I was given a Chinese Elm as a gift at the end of March.

I initially kept it in indoors, and within a few weeks, the leaves were yellowing very slightly, and I noticed some flies appearing around the base of the tree(which I think may have been fungus gnats?). I think I may have been overwatering it.

I have since moved it outside, to a relatively sunny spot, and only water once top soil appears dry, its been pretty warm though at the moment (I'm in the Netherlands), so has been daily.

However the leaves are still looking slightly yellow/red, especially the newer ones coming through.

• Any advice on what may be the cause of the yellowing leaves
• Do you think its worth re potting? Is the root system is a bit too exposed?

Thanks

 

[sorce]

Welcome to Crazy!

Sorce

 

[Forsoothe!]

That's normal and those leaves will evolve green. You should fertilize every other week to once a month with any commercial liquid at label strength. Water every day it doesn't rain. These are better outdoor than indoor trees, although they will live as houseplants. The leaves will begin to drop in January or so, and figs are better house guest, but they go both ways.

Elm are fast growers that need to be kept in-bounds by pinching the tips and/or continual trimming.

 

[Shibui]

When sun and water are covered I think fertiliser is likely the key. Give it some food.

 

[Bonsai Nut]

Welcome to the site!

The yellowish/red new growth is not uncommon with Chinese elms, particularly if they were not getting a lot of sun for a period of several weeks. Keep the tree in good conditions and fertilize lightly, and it should darken up nicely. However as others have pointed out, this is the time of year when you want to be pruning your elms to make sure they do not grow unconstrained and become mops - with interior leaves and branches dying off. There are a number of threads on this site that discuss how to prune Chinese elm - it is not at all difficult, but it is something your want to keep up with because at this time of year elms can get shaggy very quickly.

One cause for potential concern is your soil. You currently have the top of your soil covered with moss. You want to make sure your soil does not become compacted or clog. If you have lost soil (i.e. in the shipping process), it is ok to add a few scoops of fresh soil to the top of the pot. However you need to make sure that the tree is not root-bound. What appears at first glance to be soil that got washed/blown off the top of the surface might be a sign that just below the surface of the soil is a solid block of roots with very little void space for air and water. If possible, gently remove the tree from the pot to inspect the roots. The condition of the roots will determine the extent to which you can just repot the tree with a little new soil, versus needing more extensive re-potting work (cleaning out old broken-down soil and gently opening up the root ball).

Bonsai trees in pots require soil with low organic content and high inorganic content (more grit and less compost) in order to maintain void space to let in air and water. The sign that a bonsai tree is in good soil is that you can water the tree and the water will immediately be absorbed into the soil and almost instantly drain out the drain holes in the pot. If the water is only absorbed slowly, or even worse, if the water simply pools on top of the soil or rolls off the surface, you need to repot.

 

[HK90]

Awesome thanks for all the help