Your Juniper bonsai tree is dead when the roots have dried up completely you can’t save the Juniper.
You can test each branch by bending the branch. If the branches are flexible and full of sap, they will come back to alive. If they’re brittle and dry, they’re dead and will not come back to life. Some of the “brown” junipers that are still alive will put out new growth in the spring, but it will be from the ends of the branches. If the browned junipers do survive, they’re likely to be unattractive for quite some time. That might be reason enough to remove them.
What to do with dead Juniper bonsai tree
Put into the trash can / rubbish bin and reuse the pot put in new soil then plant a new seed.
Rejuvenating junipers bonsai tree
Is easy to rejuvenating junipers all you need to do is buy Automatic Dripper Irrigation Kit, put balanced fertilizer on top of the soil, Place directly at a window facing the south.wait and wait until branches turn green.
Examine your juniper, and remove each dead branch.
Maintenance pruning is undertaken by pinching the scale foliage. Take the foliage between your thumb and forefinger and give it a gentle pull. The growth tips should come off between your fingers. You hold the branch with your other hand to reduce the chance of you snapping it. This process should be done every couple of months from spring to autumn. Don’t try to pinch out more than will come off relatively easily, as this will encourage the tree to respond by putting out juvenile needle growth.
The Juniper bonsai tree should be treated with fertilized roughly once every three weeks. During the spring months, it is best to utilize a fertilizer that is high in levels of nitrogen. In the summer, a balanced fertilizer is the most optimal choice.
Repot trees that are less than five or six years old once every two years. Older plants need re-potting only once every three to five years. Repot the plants in the spring when new green buds appear on them. Keep newly potted juniper bonsais in a shady area for a few weeks after transplanting so the roots can recover.
Spray once a month with household plant insecticide. Bonsai are especially susceptible to mites. Even though you can’t see them DO SPRAY since they multiply rapidly, sucking the juices out of the plant and eventually killing it.