In October, some individuals realize that their neighbor had cut the blue hydrangeas on their property in half. Others ponder whether they should prune their LimeLight or other Hydrangea paniculata plants’ brown blossoms. The uncertainty surrounding the timing of hydrangea flower formation and how to prune them to ensure the greatest number of blooms each summer is added to these queries. What you should know is as follows:
1. The fall is not the time to prune blue hydrangeas. If you cut them back to tidy them up or make them shorter, the plants will still grow to the same height but produce fewer flowers the following year. When mopheads or lacecaps are pruned, a green dome of foliage forms on the top and only a few flowers appear in the middle and bottom, as seen in the image below. Therefore, avoid pruning them now, and the only pruning you need do in the spring is to remove any dead canes or tips. Only the canes or tops of the stems that are without green leaves at that time should be removed when pruning in late May.
2. You can prune LimeLight or other panicle kinds (Hydrangea paniculata variations) and Annabelle (one of the Hydrangea arborescens variants) in the late fall or early spring because they bloom on new growth. Some individuals like to prune theirs right now in order to get rid of the old, brown blossoms at the same time. The flowers do not need to be removed because they fall off and most of them blow away in the wintertime. However, there is no harm in trimming them off at any time from now until spring if you don’t like the way they look.
3. In April or May, prepare to relocate your mophead or lacecap hydrangea if it has grown too tall. Plan to replace the tall one with a shorter cultivar the next year because there are many great types that stay shorter.
4. Raking the leaves that have fallen under and around the plants is one of the best things you can do right now for mophead or lacecap hydrangeas; this helps keep the chilli thrips population in check. A recent insect that deforms Hydrangea leaves is the chilli thrip. To learn more, click here.
Three different varieties of hydrangeas in the fall are shown in this picture. The smooth hydrangea, H. arborescens, has an Annabellea variant, which is the plant on the left. Blue mophead sticks, or H. macrophylla, are the sticks in the foreground on the right. And a “Little Lime,” an H. paniculata, can be seen behind those in the background. The Annabelle and Little Lime can be clipped now, in late winter, or in the early spring because they bloom on new growth. The only method of pruning macrophyllas is the removal of dead stems.
This Nikko Blue Hydrangea was removed in the fall “to clean it up.” As you can see, the shrub has grown back to its original size of six feet tall and wide by the following July after the canes were chopped to a height of about three feet. Because the majority of the buds were eliminated during the “clean up pruning,” there are only a few blossoms. You will get very few flowers if you prune your blue hydrangeas in the spring or fall. Additionally, it is not possible to cut them again.
At this time of year, it won’t do any harm to remove the brown blossoms from your hydrangeas, but you are not required to. Some people worry that “ice and snow will stick to the blossoms and spit or break the limbs, but this isn’t really a concern. While those flowers are still in bloom, the Cape and Islands typically don’t get significant snowfall or ice storms in December. These bushes hardly ever sustain harm from snow, ice, or cold. Although it’s advised to “never say never,” nobody has ever claimed that their panicle hydrangeas were harmed by the cold in the 25 years that I have lived on Cape Cod. You can choose to remove the flowers or not. They break off in the middle of winter and become “Cape Cod Tumble Weeds” (I myself have never chopped them off.)
If the leaves on your hydrangeas resembled those shown below, make sure to remove all the fallen leaves and other debris from underneath the shrubs. This was brought on by chilli thrips, which overwinter in the trash. This pest can be controlled by removing the leaves and preventing them from going into the compost (burning or otherwise destroying them).
Am I able to prune my hydrangeas in November?
Pruning is not typically thought of as one of the many gardening activities that may be done in the fall, despite the fact that there are several. It can be difficult to cultivate hydrangeas successfully in New Hampshire, and if you want your plants to blossom, there is frequently very little room for error in pruning.
Wait until Spring to prune hydrangeas
In New Hampshire, hydrangeas come in a variety of kinds, and each one has quite distinct growth patterns and pruning needs. Some plants only produce flowers on fresh growth, while others mostly produce flower buds on older wood. In any case, it is better to postpone all hydrangea pruning until spring. Hydrangeas, as with all other trees and shrubs, go dormant in the fall. Not much new growth is produced by them until the next spring. As new growth is more vulnerable to harsh cold at the location of wounds, plants that have been trimmed now run a higher risk of winter damage. Additionally, fall pruning may lessen the quantity of June blooms.
Considerations for pruning hydrangea species commonly grown in New Hampshire gardens
The gigantic blue mopheads or lacecaps known as bigleaf hydrangeas (Hydrangea macrophylla), which are familiar to most gardeners, form their flower heads at the tips of stems on old wood from the previous year. Although lower buds along the stem have the capacity to grow blooms as well, the hydrangea’s blossoming potential is decreased if those buds are died or damaged throughout the winter. Wait until new growth sprouts in the spring before pruning your bigleaf hydrangeas. Approximately 1/4 inch above the first group of live buds, prune the plant. A hint: the interior of living stems will be green, whereas the interior of dead stems will be brown. Cut completely dead stems flush with the base.
The three other hydrangea species that are frequently planted in Fresh Hampshire—oakleaf (H. quercifolia), panicle (H. paniculata), and smooth—all bloom on new growth. Before the emergence of the leaves in the late winter and early spring, remove wasted flowers and prune the plant to improve its general structure and habit.
In conclusion, there are a ton of other activities you can engage in to stay occupied in the garden during fall. Save the spring for hydrangea pruning.
Cut back these shrubs in late winter before new growth begins
Shrubs that flower on young wood typically start blooming later than old-growth bloomers, beginning in June and continuing until the first frost, because they need to grow and set buds the same year that they bloom. As long as you avoid trimming when the flower buds are opening, these shrubs are understanding if it is not done at a specific period.
1. Trim the flowers all the way back for larger blooms.
These bushes can be completely removed from the ground in late winter or the beginning of spring. If cut severely like this every year, smooth hydrangeas will produce much larger flowers, but many gardeners prefer smaller blooms on stronger stems.
2. Maintain an old growth foundation to lessen flopping
Especially after watering from above or after a heavy storm, the branches of some hydrangeas frequently topple over from the weight of their blooms. Cutting the stems to a height of 18 to 24 inches will help to reduce this flopping by creating a strong framework for fresh growth.
Janet Carson is the University of Arkansas Cooperative Extension Service’s horticulture specialist.
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How far in advance should hydrangeas be pruned?
My two hydrangeas are quite robust, yet they never bloom. How far back should I clip them now, and what can I do to encourage flowering?
A: I followed up by inquiring as to when Tony typically anticipates his hydrangeas to bloom and whether or not he has been routinely pruning them.
They used to bloom in the late summer, according to Tony. He trims them to the ground in the fall.
Usually, incorrect pruning or inadequate light are at blame when hydrangeas stop blooming. It is likely that Tony’s hydrangea bloom on new wood because they do so in the late summer.
It would appear that, despite being a bit early, cutting them back at the beginning of fall has been effective for him. That shouldn’t be a problem because hydrangeas that bloom on new wood are often pruned back during dormancy, from late fall to very early spring.
Since we have a highly active deer population that regularly strips any hydrangeas they can reach, these hydrangeas are a particular favorite of mine.
Growing plants that bloom on new wood allows me to cut back on my late-winter trimming while still allowing the plants to bloom on the new growth the following spring. Deer can eat these plants.
A change in the light is another potential reason. If the plants are grown in a space alongside other plants, it is common for the flowers to diminish over time as the neighboring plants swell and cast more shade.
Although hydrangeas are actually understory plants, we tend to think of them as shade plants. As the amount of shadow rises, however, fewer blooms are produced.
Another option is that there will be more deer, or that a herd will move into Tony’s area, which happens frequently whenever there is new construction, whether residential or commercial, which drives animals out. Deer can cause damage as they travel into places that weren’t previously hotspots since they eat throughout the year. Deer tend to eat delicate shoots and buds from plants.
For instance, we have spent around 17 years in our current house. My hostas and daylilies were mostly unharmed during that time. Nearby, significant projects have been constructed over the past few years, decimating my hosta bed and removing the buds from my daylilies.
This year, we even saw fawns hiding in the front yard by some plants. A bush outside my kitchen window with lovely white variegations on the dark green leaves was one of my favorites, but others, like hydrangeas on a steep slope, have been eaten down.
A: I’ve pruned two out of the three hydrangeas in Westmoreland County, southwest Pennsylvania, just south of Greensburg. I typically trim down 3 feet or so when they reach a height of approximately 9 feet. I was unable to reduce the last one this year because to weather and a backache. Do you believe cutting the final one now will affect No. 3 more than waiting for a day or two of 40 to 50 degrees, which it appears may occur? Or could you just trim the edges off the flower? Thanks.
A: Tom must respond to the same inquiries I posed to Tony. He typically prunes while the hydrangeas are in blossom. It is too late to prune the plants back without losing at least some of the flowers for the following year if they bloom on wood from the previous year.
He ought to be able to remove the dead blossoms without losing any flowers. Tom should trim the wasted flower stem back to just above the next node (where the leaves or branches emerge from the stem).
He can safely cut his plants until early spring if they bloom on new wood because the flower buds for the following year have not yet formed.
Another choice is to do nothing; although his hydrangea will grow bigger the following year, it won’t suffer from lack of pruning. Cutting off the old blooms is a possibility in both situations—new wood and old wood—even though some plants produce hardy flowers that provide the barren landscape some winter charm.
I observe that it is wise to remove old stems from hydrangeas when pruning in order to keep the interior light- and airy-filled. It would be preferable to begin by performing some basic maintenance trimming before chopping back the branches, even though he may be pruning for size. Prior to trimming the length of the remaining branches, look for any broken, diseased, or rubbing branches.
More on holiday plants
I talked about some of the popular tropical plants used for decoration last week. Others, like holly, mistletoe, and cut greens, have the opposite requirements.
Despite appearing to be evergreen, all of these plants require moisture, so you should think about misting them, especially if you plan to exhibit them indoors.
Holly is actually better kept outside since, as they dry and fall, the prickly leaves hurt to touch. Additionally, the holly lasts a lot longer outside.
Another plant that needs particular care is mistletoe. Most sprigs have fake white berries, but others have actual ones. Watch out for any dropped mistletoe berries because they are deadly, especially if you have or anticipate guests who will bring pets or small children.
The greens, wreaths, and garlands are intended for temporary inside display, so it’s time to move them outside when they begin to lose a lot of needles or turn brown.
If you utilize cooler LED lights instead of hotter incandescent ones, the displays with lights will last a lot longer.
Week in the Garden
Planting:
- To add color to the winter landscape, use holly, miniature evergreens, cut greens, and pansies.
- Remaining spring-flowering bulbs should be potted and kept at a cold temperature of 40 degrees or lower for 8 to 12 weeks before being brought inside for forcing.
- Plant seeds that need a period of cold weather for germination.
Seasonal:
- Buy Christmas presents and gift cards for gardeners on your list.
- Clean, examine, fix before hanging decorations, and throw away broken ones. Secure all decorations to prevent loss or damage during windy or stormy conditions.
- Clear dead plants and leaves from paths.
- Permit seed-producing plants to stay on the plants so that wildlife can eat them.
- Find a planting location, dig the tree out, and put the soil in the garage if you are buying a live Christmas tree in a pot or wrapped in burlap.
Lawn:
- On the grass, rake, blow, or mulch fallen leaves. Matted leaves can prevent water from reaching the soil and promote mold issues.
- Water freshly seeded or sodded lawns until the ground freezes, and provide additional watering during weeks with less than an inch of rainfall.
Chores:
- To prevent winter damage, bring mobile pots and garden ornaments inside, or wrap large statues. Terra cotta, clay, or plastic empty pots should be kept in a dry, protected environment to prevent breaking.
- Till extremely early spring or late winter, stop pruning.
- Mark off new plantings, beds, delicate plants, and plants that are slow to emerge from winter dormancy in the spring. When decorating or removing snow, stay away from them.
- When the ground freezes, spread mulch for the winter.
- To check for new growth, inspect stored amaryllis bulbs. Water, followed by a warmer location and gradually increasing indirect light.
- Garden waste should be removed and composted. Get rid of or destroy sick or infected plants.
- Topdress now with compost or manure, then till the following spring.
- Until the ground freezes, water any new crops whenever we go more than a week without receiving more than an inch of rain.
- Check the caulking on the windows and doors. Make repairs right away to keep mice, ladybugs, and stink bugs out.
- Remove any standing water.
- Protect delicate plants from deer, rabbits, and groundhogs. Reapply taste or odor inhibitors.
- Regularly clean and restock bird feeders. Clear away the empty hulls and spilled seed. At least once each week, empty, scrub, and refill birdbaths. In cold weather, think about getting a heater.
- Rainwater runoff should be directed away from building foundations by clearing gutters.