I heard ashes from wood was a very good fertilizer for hydrangea bush...is that correct? Would this work for clemitis vines??
If you want blue hydrangea flowers don't apply alkaline materials like wood ashes. Clematis might do OK with it. As with purchased fertilizers best not to put on substantial doses of nutrient sources without sampling the soil and having it tested first, or having some other basis for knowing what the nutrient situation in your soil probably is. Fertilizers can be overapplied and produce a toxic situation, with plant growth being affected. Perhaps the most common overfertilization problem in home gardens is the overapplication of phosphorus.
If you increase the acidity of your soil around the base of the Hydrangea, you will end up with Blue flower heads. If you add the ash and reduce the acidity to the level of a lower ph, then you will have pink flowerheads... now you may want to test your soil? If the hydrangeas are under an evergreen such as Cedar or Douglas fir, the soils acidity level will be high.
