I cant speak to mugo pines, but for the Chinese elm they are more vigorous growers if they go winter dormant. This can mean in it's pot outside, if your temps rarely go below 30F, or buried in the ground outside over winter, or even kept in an unheated shed or garage where winter winds won't dry it out. Thus, the soil will generally be frozen hard as a rock, and ice will insulate the roots.

When it begins to wake up in the Spring (leaf buds just beginning to swell) is the best time to repot. You can research bonsai soils and create your own designer mix. If you're just learning how to keep the darned thing alive, you might have enough studying to do and want to just buy a premixed soil blend. Good ones generally have little or no potting soil in them.

Your research could include Bonsai Jack's website, because there is explanation of their different soil components and why they choose them for the soil mixes they sell. For budget concerns, honestly a cactus soil from the local nursery is preferable to potting soil for bonsai.

ez

Thanks alot ez for the tips. Ive been trying to do any much research as I can and will continue. Thanks again.

You're welcome, and I hope someone comes along to provide some guidance on the mugo pine.

ez

Mugos do not like to be sitting in wet soil, but unlike other pines, they react best to repotting in summer. You should not wash the roots, because that will remove the natural mycarrhizae which it needs. For my pines, I use mostly Turface (calcined clay)with some chopped conifer bark added. For now I would just not water it until nearly dry, and keep the soil and pot mulched to protect the roots from freezing hard.

Okay. That helps a lot, thanks.