Geraniums are naturally straggly. They are not bushy plants. If you wanted a naturally bushy shrub, you’d be re-planting pelargoniums annually.
The fact that you are here to learn about how to make geraniums bushy means that you are growing a true hardy geranium. They naturally grow thin and straggly. They need to be trained to develop a bushy appearance. Think of hardy geraniums as the bonsai of the shrub kingdom.
Pinching is the Start of Training a Geranium to Grow Bushy
Without regular pinching and pruning, some species of geraniums can grow to 4 feet tall with a 3-foot wide spread. It will look spindly. Pruning is done to keep the height and width of the bush in check, but pinching is how you encourage fullness.
When pinching your plants, make the cuts (or snaps) just above a leaf node. There are two types of nodes. Inward facing and outward facing nodes.
The outward facing ones are the ones you want to keep. The inward facing nodes ought to be removed.
The reason to rid your plant of inward growth nodes is to maintain good air circulation. Should excessive inward growth occur, air ventilation becomes restricted, then you get a myriad of problems.
What is the Difference Between Pinching and Pruning Geraniums?
Young geraniums grown from seed begin life as a single stem that grows straight upwards towards the sunlight. As it grows, auxiliary nodes are produced, which then form the leaves.
The plant will continue to grow directly upwards in this natural upward straggly growing pattern until you (the gardener) intervene.
Pinching Geraniums Is the Necessary Intervention Required for Bushy Growth
The sooner it’s done, the bushier the plant grows. The downside is that flowering happens later in the season, but it is worth the compromise for a properly filled out bushy geranium.
When you remove one auxiliary bud from the stem of a geranium, it produces two more side buds.
That, above, is how to make geraniums bushy. It stops the straggly upward growth, encouraging more side growth. The plant will take years to reach a few feet in height, but as it grows, it grows in fuller.
Once young geraniums begin to get established, pinch back new growth by one-third. New stems emerge. Leave at least a few leaves on each stem so as not to reduce photosynthesis.
Removing too much foliage prevents the plant getting the energy it needs from sunlight. The more leaves it has, the better it grows.
As those new stems grow in, continue pinching those back. After several weeks to a month, you should start seeing your geranium develop more bushiness.
Hard Pruning Geraniums (Spring or Fall)
True (hardy) geraniums benefit from a hard pruning, meaning a lot of foliage is removed. This can be done on mature geraniums in spring OR fall. Not both. Only hard prune once per year on these plants.
There is no right or wrong season to prune. Either way, the foliage will die. Prune in the fall and it’s essentially removing the foliage before the cold weather kills them. Prune in the spring, you’ll be removing the brown dead foliage.
Deadhead Geraniums for Continuous Lush Blooms
Summer pruning is when to be on your A-game with geraniums. As soon as flowers start to brown, fade, or lose their vibrancy, remove them from the plant. However, unlike with pinching the stems, you do not want to keep the main stalk on the plant by only pinching the flower head.
Remove the flower stalk when deadheading geraniums. Go further down the plant stem that has the flower head and remove the stem the flower is on. That forces a new stem to grow in, and then that produces more flowers.
If you only pinch off a flower head, the main stalk will not have sufficient energy to produce a new flower.
Consider geraniums to be plants that flower once per stalk. Remove the stalk, a new one returns, a new flower bud emerges and then that blooms.
Geranium Nutrition: Here’s What They Need to be Fed
Like every plant, the main nutrients geraniums require are potassium, phosphorous, and nitrogen. You can meet that easily with any balanced fertilizer (balanced being 10-10-10 or 20-20-20) all-purpose fertilizer. Give them a feed once every three to four weeks.
All-purpose fertilizers lack many of the trace minerals plants require. The type you need largely depends on what’s in the soil your plants are using to feed from. A quality soil provides much of the trace minerals required for geraniums, but not always everything.
One to monitor is magnesium levels. A sign of magnesium deficiency is yellowing leaves on geranium plants. Yellow leaves can be a sign of nitrogen deficiency, however, that same problem can arise when the plant struggles to uptake nitrogen from the soil.
If you mistakenly treat yellow leaves with higher nitrogen fertilizer, it can lead to fertilizer burn. Start by upping the magnesium levels by occasionally feeding Epsom Salts (magnesium sulfate). It doesn’t directly bump up nitrogen, but as a complimentary plant nutrient, it helps the plant consume more of what’s already present.
Important trace minerals specific to geraniums include sulfur zinc, copper, iron, manganese, boron, and calcium.
Knowing that, the best fertilizers for geraniums will be 10-10-10 or 20-20-20 all-purpose fertilizer which include traces of each element mentioned above.
Priority Tip: Plant in a Bright Location. Otherwise, it WILL Grow Spindly.
A sure-fire sign of a lack of light is leggy or spindly growth. When geraniums grow tall and thin, it is because the leaves are stretching for sunlight.
Geraniums need four to six hours of full sun daily. If they are receiving dappled sunlight, such as if you have your geranium planted under the canopy of a tree, it will need longer.
The lack of sunlight is what causes the stems to reach for the sky. The result is a straggly looking geranium plant instead of a lush and colorful bush.
How to Recover a Leggy/Overgrown Spindly Geranium
Leggy geraniums are unsightly. The majority of the time, it is either the result of improper pruning maintenance, or a lack of sunlight causing them to stretch towards light.
Pruning a plant that has been growing for a year or two can feel daunting. It is beneficial though. These plants are tough, can take a thorough cutting back and still rebound viciously.
As geraniums are fast growers, there are two approaches to hard pruning the overgrown shrub. You can go at it ferociously by cutting it all back to a few inches above the soil level.
Or, you can take the longer-term approach which is to trim it back gradually over a three-year period – removing one-third of the plant the first year, half of new growth the next, then start regular geranium pruning to force it into a filled out bushy geranium from the third year, and every year thereafter.
The three-year approach is better suited for geraniums that have been left to grow wildly. Such a scenario can happen if you move to a new property where the garden stopped being maintained for whatever reason. These overgrown plants may have a lot of healthy growth on them, but need to be pruned to give the shrub a desirable shape.
For a three-year project on a heavily overgrown geranium, make the cuts for each branch at the base. Not the middle, or nearer the top which would only remove the leaves.
Take the entire branch off. Do this for no more than one third of the plants size in the first year’s cutback. The second year, cut away 50% of the oldest branches that remain, keeping the new branches on the bush.
The third year is the start of annual pruning, which is when to start shaping the plant. This method lets you keep the vast majority of the height and spread, negating the need to cut it back to near-ground level.
How to Hard Prune in One Go Without Killing Your Geranium
Split Overgrown Plants into Sections
With a heavily overgrown geranium, you’re essentially cutting it back to the bare minimum it needs to grow in fuller. That’s around 3 to 4 inches above the soil line.
Before drastically cutting the plant back, see what actually needs to be removed. Start with the longest stems with little foliage.
It may help to use plastic ties, or string to tie some of the stems together letting you see different sections as you work your way through each. Start with the longest and thinnest stems. These will have the leaves at the branch tips with very little side shoots.
The side shoots are what make geraniums grow in fuller. Any stems with no or very few side growth buds, cut them off. The new ones will grow these because you can train them to split one stem into two by pinching the tip ends, as discussed above at the pinching stage.
Tools to Use for Cutting Geraniums Back Hard
Bypass Pruners or Bypass Loppers
The stems can be cut with a sharp pair of scissors. For the chunkier woody growth near the base, a sharp pair of bypass pruners will make cleaner cuts. Do not use anvil loppers!
The difference between bypass and anvil loppers are that bypass loppers have two blades. Anvil loppers have one sharp blade that pushes the material against a flat plate, effectively crushing the material rather than cutting it cleanly.
Anvil loppers are for preparatory cuts. Bypass loppers are for finishing cuts.
Rubbing Alcohol (Isopropyl 70%)
Use rubbing alcohol to sterilize your gardening tools before making cuts. On overgrown geraniums, whiteflies, aphids, mealybugs, and spider mites are a risk because there is plenty of plant juices for them to feed on.
If these were ever present, the rubbing alcohol prevents any larvae or bacterial disease from spreading throughout the plant from the scissors or pruners, and protects your other plants too.
Decide on Composting or Propagation for Cuttings
Given a lot of cuttings are being removed from an overgrown geranium, it will be helpful to know what you’ll do with all those cuttings. With proper geranium care from the start, new plants can be rooted in single pots either for your own use, as gifts, or possibly resell them locally, or online.
At the very least, have a compost bin at the ready. You could easily trash them or even burn them (where bye-laws allow garden incineration), but given most of the cuttings will be healthy, trashing or burning would be a waste.
Annual Maintenance Geranium Care Tips
Prune Heavy Once per Year
Every year, hardy geraniums go into a dormancy period over the winter. The majority can withstand colder temperatures. They do not grow, but most won’t die.
That is dependent on your climate. If temperatures are consistently below zero, cut back the geraniums to three to four inches in the fall then overwinter the plant indoors.
For modest winters, a good thick layer of mulch is often sufficient for geraniums to survive the winter outdoors.
Spring Prune to Prepare for Blooms
The first cut of the year is the spring cutback. At this stage, inspect the plant for brown or fading leaves. Those are the first to go as they do nothing for the plant.
Feel the stems for rigidness. Any stems that feel mushy, cut those off. Healthy stems will feel firm when gently squeezed.
Summer Prune for More Vibrant Blooms
The summer is deadheading season. Removing spent and fading flowers by snipping off the stems that the flower buds grew on.
At the minimum, geraniums need to be pruned at least three times per year, not including regular deadheading of spent flowers throughout the season. Spring or fall are the best time of the year to prune geraniums for shape to encourage bushy growth.
Geraniums are wildly popular because they are advertised as being easy to grow. That, they are. But, they are not bushes. They are shrubs that naturally grow tall and thin.
To make a geranium bushy requires regular pruning to shape the plant, otherwise it will just keep growing upright.