I took a hardwood mulberry cutting this winter. It's inside under a skylight and has grown some buds which (as well as already present buds) are now breaking into leaves. It might be just saved up energy in the stem though. I fear the leaves might suck the cutting dry. I keep the ground moist and mist the cutting whenever I'm home and see the hardwood has become a bit dry.
Now that leaves are forming, should I provide a more powerful light source? Indirect, more direct or LED grow light to (hopefully) promote root growth?
I read a lot about how to start the cuttings but nothing about this stage.
I would presume that you did them outdoors and that ordinary sunlight would fine during the summer- just don't let them dry out- the problem with mulberries is they don't like to be pruned and the wood needs to be sutured and burnt to stop it bleeding afterwards, I would leave them for quite a while to allow root formation depending what it is you're growing them in. normally hard wood cutting are healed in a trench in groups or in a line, planted about 3/4 depth of the length of the foot long pencil thick cuttings - usually in a rooting medium of a mix of good soil and grit- usually done outside- light not being a problem, however if there's life already- you must be doing something right! For problems sake I would harden them off to a brighter source of light gradually and shade them on bright days at first(burning the leaves off or scorching them isn't a good idea)- treat them like its hardening them off to cold conditions outside but with light not warmth- if you see what I mean? eventually they should be alright in normal light by the end of summer- just remember they are deciduous and if you keep them indoors they can hold onto their leaves all winter sometimes- shouldn't affect how they will eventually grow like when placed in the their final positions outdoors. And yes mulberries will grow quite big outdoors unless its one of those miniature varieties that where introduced earlier this year.