Answer: Based on your description, I am not certain what is happening to your junipers. Before you replace them, you should try to figure out what happened. Drying up can signal root damage due to being planted in a poorly drained location or to over or under watering. It can also be due to poor planting practices.
Junipers require full sun and a well drained soil, meaning they must not be planted in a place that stays soggy or in a low spot where water or snowmelt collect.
They are very drought tolerant once established, but would need careful watering during the first year. (All new plants need careful watering the first year.)
Your goal in watering is to keep the soil evenly moist like a wrung out sponge, not sopping wet and not dried out. To know if you need to water, dig into the soil with your finger. If it is still damp, do not water yet. When you do water, apply it to the soil surface and water thoroughly and slowly so it soaks down to the deeper roots. After watering, wait a few hours and then dig down to see how far the water soaked in; it can be surprising.
There is no set schedule for watering, it depends on your soil type and on the weather. Using an organic mulch several inches thick over the root area will help reduce watering needs as well as feed the soil gradually as it breaks down over time.
The junipers may have failed to root into the surrounding soil, thus causing them to dry out. This can happen if they are planted too deeply, if there are encircling roots that are not unwound or cut at planting time, or if they are set into holes that are poorly prepared, or if they are planted into a heavy clay soil.
You may want to consult with your local county extension and/or with a professionally trained and certified nurserman to try to determine what is causing the problem. Based on knowing that, you can decide what to do.
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