Brown County University of Minnesota Master Gardener
Each year, lovely hydrangea bushes will reward you with gorgeous blossoms that will instantly transport you back to your happy youth. Who could forget the white hydrangeas with their snowball-sized blossoms. We would have been astounded by the size as kids. Growing hydrangeas is enjoyable since we are still amazed and amused by them as grownups. They are also highly resilient and resistant to most pests and diseases, making it even easier to care for hydrangeas. You are sure to find one that is perfect for you because there are so many different types.
Planting is best done in the spring and fall. Plant in the springtime when the risk of frost has passed. Place your hydrangea in a location where you won’t need to prune it. These shrubs have a robust growth rate, and they are naturally large and attractive. Your hydrangea shouldn’t be planted any deeper than it was when it was in the pot. Planting beneath trees should be avoided since the roots will fight for moisture and nutrients. For the first few years, give your hydrangea enough water to help the roots grow strong, but don’t let the water pool around the plants. Use a balanced, slow-release fertilizer once a year, or apply 10-10-10 twice a year. Compost or commercial manure are both organic substitutes. By August, stop fertilizing to allow your hydrangea to prepare for dormancy.
Though there are many different varieties of hydrangeas, the majority may be grown in some shade. They do need four hours of sunlight each day. However, a lot of hydrangeas dislike really hot weather, so try to place them where they can take advantage of some afternoon shade. While they can be grown in a broad range of conditions, hydrangeas normally require rich, moist soil that drains smoothly. Before planting, amend the soil with compost to help loosen it. After planting hydrangeas, mulch can also be added.
When taking care of hydrangeas, water is crucial. At least once a week, especially in dry conditions, they enjoy deep watering. Hydrangeas can also be transplanted easily, although this should only be done during dormancy in fall or early spring. Make sure to remove the entire rootball before planting it again right away.
Hydrangeas come in a variety of varieties, and each may require somewhat different trimming and care. Before making a purchase, carefully review the plant tag for details, zone hardiness, when to trim, and whether it needs sun or shade so you can plant in the appropriate location.
Types of hydrangeas, sometimes known as hydrangeas:
Round, globular flower heads can be found on mopheads. The majority enjoy early sun and afternoon shade, but they avoid strong shade because it can result in subpar flowering. Along with white, lavender, and lilac, they also come in blue and pink. The flower heads of H. macrophylla normalis, which is also known as lace cap hydrangea and has the same fundamental growing needs as mopheads, are made up of considerably bigger sterile male flowers in the outer ring and tiny disk-shaped fertile flowers in the center. Flower heads on lacecaps are loosely placed and flattened. This gives the garden a very different appearance. Because they generated flower buds on last year’s stems or the old stems, these hydrangeas were frequently challenging to coax to re-bloom in cold climes. The new stems formed during the season were unable to bear blooms if they suffered severe winter damage and died to the ground. Since then, new macrophylla varieties that bloom on both old and young stems have been introduced, changing this. Gardeners now have a chance to blossom even if stems are completely destroyed. Verify the growing zone on the label (some zone 4, but most are zone 5).
Smaller shrubs called H. serratas are a subspecies of macrophyllas. Shade them partially. H. arborescens, often known as smooth or wild hydrangea, makes a lovely addition to any garden. The most popular cultivar is “Annabelle,” which consistently produces large, white blooms. The Hydrangea paniculata species are among the most tolerant of urban environments and adaptable hydrangeas. These plants favor either full sun or partial shade, well-prepared, wet soil.
The University of Minnesota has identified the following cultivars as hardy in Minnesota. Although the University does not advocate any particular types, it does provide the following for you to take into account for your garden:
One of the most well-known names for hydrangeas is Annabelle. Annabelles, often referred to as Snowball hydrangeas or smooth hydrangeas, feature enormous, symmetrical blooms in the months of June and July. It can get up to 4-5 feet tall and 3-5 feet broad and is hardy to Zone 3. With creamy white flowers that are frequently more than 8 inches across, it is likely the most showy hydrangea in the garden. Rich, well-drained soil that is regularly moist is what Annabelle prefers. It thrives in some shade and tolerates a wide range of soil pH levels. If it is planted in full sun, make sure to water it enough to prevent the leaves from drooping. Each spring, just as the new buds start to appear on the lower stems, Annabelle needs to be cut back to within a foot or two of the ground since it blooms on new wood.
The first pink-flowering ‘Annabelle’ hydrangea is called ‘Invincibelle Spirit. From summer through fall, this plant produces a ton of bright pink blossoms, and the color is unaffected by the pH of the soil. It can reach heights of four to five feet.
Incrediball is an enhanced version of the tried-and-true “Annabelle.” The blossoms are enormous, measuring up to 12 inches in diameter, as their name suggests. The stems are also much more sturdy than those of “Annabelle,” allowing them to support the heavy flower heads and prevent them from drooping. Incrediball may reach heights of four to five feet.
The name “panicle hydrangea” also refers to Hydrangea paniculata ‘Grandiflora’. PeeGee is a robust cultivar that can withstand Zone 3. In August and September, it blooms in a spectacular conical shape. They start out milky white and fade to a lovely bronze-pink that lasts well into the fall after a few weeks. The shrub will expand to a height and width of 8 to 10 feet in our environment. The ideal soil for PeeGee hydrangeas is loamy, evenly moist, and well-drained. They can thrive in both full sun and partial shade and are pH-adaptable. Any pruning should be done in the spring since they blossom on new wood. Because PeeGee hydrangeas are so resilient, dieback is rarely an issue.
Limelight hydrangea paniculata Limelight is hardy to Zone 4 and is related to PeeGee hydrangea. It varies from PeeGee by flowering later and having flowers that are a vivid lime green. With a height and width of 6 feet and 8 feet, it develops into a rounded shrub. Make sure to give it a lot of room to expand. Limelight thrives in both full sun and partial shade. It will offer bloom in the late summer and early fall. Limelight blooms develop on young wood, and early spring pruning is advised. It tolerates a wide variety of pH levels and does best on loamy, well-drained soil.
When is the best time to plant hydrangeas?
Learning the fundamentals of how to plant hydrangeas can help you save time and money, just like with most other items in your garden. You’ll improve your chances of enjoying big, vibrant hydrangea flowers for years to come by picking the appropriate site, getting the soil just right, and planting correctly.
Best time to grow hydrangeas
The best time to grow hydrangeas is in the fall, followed by early spring. The goal is to provide the shrub lots of time to develop a strong root system before it blooms. Early in the day or late in the day are the ideal times to plant. The day’s cooler hours provide relief from heat exhaustion. Water new plants frequently until they get established.
Locations to plant hydrangeas
The first step is knowing where to grow hydrangea plants. Hydrangeas are frequently grown in beds adjacent to houses or fences. This is so because hydrangeas prefer the mild early sun to the hot afternoon sun. A protected area with sunny mornings and shaded afternoons is the ideal spot to plant hydrangeas. This is frequently found on the north or south side of a house. Avoid planting underneath trees since it could cause competition for nutrients and water. Flowers and leaves can both be destroyed by strong winds.
hydrangea-friendly soil
The soil needs to be rich in organic matter for hydrangeas to thrive. Drainage is important. Although hydrangeas prefer damp soil, they cannot stand standing water. Root rot can be brought on by wet, poorly draining soils. Your hydrangeas could pass away in a matter of weeks. Consider adding a lot of compost to your heavy soil before planting to increase the soil’s quality.
Methods for planting hydrangeas
Simply dig planting holes that are 2 feet wider than the root ball for planting hydrangeas. So that your plant lies level with or just higher than the surrounding soil, match the depth of the hole to the size of the root ball. You can improve water drainage away from the plant’s base by making a small mound.
The best way to grow hydrangeas
Simple propagation methods can multiply a single hydrangea into several more. The optimal time to layer bigleaf and panicle hydrangeas is in the early to mid-summer. You only need to:
- Close to your hydrangea plant, make a tiny trench.
- Bend a branch such that the middle of the branch meets the earth in the trench (six to 12 inches of branch should extend past the trench).
- Where the branch meets the trench soil, make scuff marks on the bark.
- After the trench is filled, cover it with a paver, brick, or stone.
- The branch can be transplanted to a different area once it has established its own root system over time.
Hydrangeas with smooth or oakleaf leaves produce new growth from underground stems. Simply separate the baby plant from the main plant by digging it up. After then, it can be moved to a new spot.
Can hydrangeas be planted in Minnesota?
This Debbie Lonnee essay was published in Northern Gardener’s September/October 2019 edition.
The panicle hydrangea, also known as Hydrangea paniculata, is the most vibrant plant in the late-summer landscape. In Minnesota, we can grow it since it is one of the hardiest hydrangea species.
I’d like to show how one of the several new cultivars available today can be grown into a different shape or form rather than highlighting one of them.
You generally picture a spherical, bushy multi-stemmed plant when you think of a shrub. You probably picture a tree as having a single trunk and a branching crown when you think of them. Why not combine the two and create what my coworkers and I affectionately refer to as a “shrub on a stick”?
Hydrangea paniculata is increasingly frequently used in this manner, and a well-shaped tree form is a pleasant addition to landscapes with limited space.
A good-sized panicle hydrangea tree takes the nursery grower more than five years to produce and market. Without going into too much technical detail, the growers start with a young, rooted cutting, remove all but the strongest, straightest stem to form a trunk, and then trim the trunk at a specific height (often around 4 feet) to form a shrubby, round head. These bareroot trees are either harvested and transported to other farmers, or they are planted in bigger containers, usually 7- or 10-gallon ones, and after another year of rooting and growth, they are shipped to garden centers. These plants have the appearance of an elegant young tree with a prominent trunk.
The production of trees typically employs the taller panicle varieties. Consider outstanding cultivars like Quick Fire, First Editions Vanilla StrawberryTM, and “Limelight” PP12,874. These are the best types for trees because they all reach maturity at a height of 6 to 8 feet. The more recent dwarf varieties don’t work well as trees. Beginning in July, the conical flowers bloom throughout August and into September.
So, how do you cultivate and care for a hydrangea in tree form? They have the same environmental requirements as shrubs: full light and average soil that drains well. The majority of cultivars are hardy in USDA Zone 4, and several are also hardy in Zone 3. The primary distinction is pruning. Panicle hydrangeas can be pruned in March, April, or early May since they bloom on new wood. For the first few years, you’ll need to be particularly vigilant with a newly planted tree to keep the tree’s round shape. Don’t be afraid to trim the stems back by 25 to 50 percent when you prune to ensure that the plant continues to have a spherical shape. Any branches that develop on the trunk can be readily trimmed to preserve the trunk’s appearance.
In the spring, a mild fertilizer is beneficial. These miniature shrubs on sticks provide a plant that resembles a tree in the landscape but takes up very little room. The verticality of a tiny tree will be advantageous for gardens in townhouses and small city lots alike. They are used by many designers in huge display pots, but they must be kept indoors throughout the chilly Minnesota winters.
Just a few observations regarding the three cultivars I have previously suggested:
PP12,874 for “Limelight” This outstanding cultivar, from the Proven Winners Color Choice program, is a great tree. Midsummer sees the flowers bloom, first a lovely white, then a lime green. The blossoms will develop some light pink, burgundy, and green tones as they ripen.
Strawberry Vanilla First Editions This French-bred panicle hydrangea was one of the first to exhibit stunning pink and strawberry hues as the panicle grew. The color first appears as white, and then at the base of the panicle, it takes on color. When we experience chilly overnight temperatures in late July or early August, this color is at its most vibrant. The last two seasons, this cultivar has displayed stunning color. A plus are the red stems.
‘Bulk’ Quick Fire PP16,812 One of the earliest panicle types to bloom in the summer, sometimes a month earlier than other varieties, this plant is a part of the Proven Winners Color Choice program. Although the flowers are more open than other kinds, they are nonetheless lovely in their own right. As the blossoms ripen in August, Quick Fire will start to take on some pink hues.
When can my hydrangeas be planted outside?
Choose a time in late spring or early fall when the nights are cooler and there is little risk of frost. If you garden in an area where the ground freezes, put seeds at least six weeks before the first deadly frost of the fall. This allows plants to establish roots before the ground becomes really cold. To improve root insulation, place a 2-inch mulch layer around plants after planting.