Hydrangea Questions
At Gertens you can find four different types of Hydrangeas: Hydrangea quercifolia (native to the USA), Hydrangea arborescens (native to North America), hydrangea paniculata (non-native),and hydrangea macrophylla (non-native).
Quercifolia: Also known as Oakleaf hydrangea is hardy to zone 5a. There is a heat island in Minneapolis that’s zone 5. You can also plant this in an area protected by wind. Mulch well at planting and add more mulch after ground freeze...
With new advanced breeding, Hydrangeas can range from 1.5 feet tall to growing upwards of 10-15 feet tall!
Most of the Hydrangeas should get a minimum of 5-6 hours of sunlight a day for full bloom (each type might be a little different). Only the Arborescens type (Annabelle) will do well in shade. They will need 3-4 hours of sunlight to do well.
Some recommendations for healthy Hydrangea’s would be to protect the plants during the winter, use a good bloom enhancing fertilizer (something with a high phosphorous number, middle number on packaging), and make sure to not overwater.
1) Nitrogen (leaf development, top growth) 2) Phosphorus (roots and blooms) 3) Potassium aka Potash (roots)
Use a bloom enhancing fertilizer, make sure it has a high level of phosphorus (middle number of NPK) for full blooms.
The recommended root stimulator for Hydrangeas would be the Plant Starter Solution (4-10-3) .
Root stimulators provide a hormone to the root system to recover faster from any damage done during the transplant process. This will also help the roots grow faster and stronger.
Hydrangeas prefer loose soil with high organic matter, really everything but the most compacted soils.
Mulching your Hydrangeas is absolutely recommended. Mulch helps to maintain soil moisture as well as regulate temperature. Mulch can also help keep insects at bay. Gertens experts recommend using Western red cedar mulch.
Thin out hydrangeas in the springtime as necessary for new growth to thrive. Don’t prune a Macrophylla Hydrangea in fall, the canes will protect the plant during winter. You can prune out dead wood at any time.
Full sun is six or more hours of direct sunlight, part sun is four to six hours of sunlight including some afternoon sun, part shade is four to six hours of sun before midday, full shade is less than four hours of sun.
Use a slow-release plant food in spring, April to May. Read the label for application, water well and the fertilizer will feed the plant for the rest of the year. NPK of 12-12-12 is recommended.
Transplant either in early spring or later in fall when the weather is cooler. Have your relocation hole already dug. If the plant is up to 5 years old, dig up as much of the root system as possible and move to the new spot. If the plant is older than 5 years old, take as much of the surrounding soil of the root ball for the best chance of survival.
Leave the dead flowers up for winter interest. In spring, follow the stem until you get to new growth, then go up about half an inch and make your pruning cut at an angle.
You can do rejuvenation pruning on paniculata type hydrangeas, but it will take a few years to reshape itself and get back to its full potential. If you have questions, or need further assistance, feel free to bring pictures into our Gerten experts.
When the leaves on your Hydrangea plants first start showing up, put some Repellex into the ground (follow directions on packaging) and then again about a month later. This product will make the entire plant taste like a hot pepper, the rabbits and deer hate it and will keep away. This solution will last all year long.
No, not all Hydrangeas are winter hardy. You need to check the hardiness zone for which plant you are planting. If zone 5, make sure to protect these for the wintertime.