Raspberry canes can grow quite tall, sometimes up to six feet (182.88 cm) tall. And while this might not seem like a big deal, it can be quite a nuisance. Tall raspberry canes are more likely to fall over and be difficult to pick. But why are they so tall?
Your raspberry canes are tall because of the age of the plant, the variety, and the amount of sunlight the plant gets. As the plant gets older, it will produce taller and taller canes. Some raspberry varieties are also known to have taller canes than others.
In this comprehensive guide, I’ll discuss why your raspberry canes might be tall and how to keep them under control. So, whether you’re a beginner gardener or a seasoned pro, this guide will help you understand why your raspberry canes are so tall.
Reasons for Tall Raspberry Canes
Here is a lowdown of the top reasons why your raspberry canes are tall:
1. The Age of the Plant
Raspberries can live for up to 15 years and generally produce fruit for at least 5 years, with some varieties producing for more than ten years. After that, the plants start to decline in vigor and productivity.
Raspberry grows in stages:
Stage #1: Primocane Production
The first stage is when the plant produces new canes, called primocanes. These canes are thinner and shorter than the mature canes (or floricanes) that will produce fruit the following year.
Primocanes can grow up to 5 feet (1.52 m) tall, and as they mature, they will produce fruit the following year. The promicanes grow in the first to second year.
Stage #2: Floricane Production
The second stage is when the plant produces fruit-bearing canes, called floricanes. These canes are thicker and taller than the primocanes and can grow up to 8 feet (2.44 m) tall.
Floricanes produce fruit in their second year and then die off. The plant will produce new primocanes to replace the floricanes that died off. This cycle repeats itself every year.
So, if your raspberry canes are tall, they could be getting old. The primocanes and floricanes go through different stages of growth, which can affect the height of the raspberry canes.
2. Raspberry Variety
Some raspberry varieties are naturally more compact, while others can grow quite tall. These varieties include red, purple, and black. Yellow raspberries belong to the red raspberry but do not have the red pigment.
The black raspberries, also called blackcaps, are among the tastiest of all raspberries. They are pretty small and delicate, but their compact growth habit makes them perfect for containers.
The primocanes of black raspberries can grow up to 2-3 feet (0.61 – 0.91 m) tall, with Jewel raspberry being the most popular variety. Red raspberries can grow to lengths of up to 6 feet (1.83 m), with varieties like Boney being prevalent.
The canes are quite thin and need support to prevent them from falling. This growth habit makes them less ideal for pots. Purple raspberries are a cross between the red and black varieties.
They have the flavor of black raspberries with a sweetness like that of red raspberries. Purple raspberries are not as tall as red raspberries and are slightly taller than black raspberries, with a height of 4-5 feet (1.212 – 1.52 m). There are two types of purple raspberries, the Brandywine and the Royalty.
3. Environmental Factors
The temperature, humidity, and soil type can all affect the growth of raspberry plants.
Raspberries prefer a cool climate and will not tolerate temperatures above 78 °F (25.55 °C). You may notice a raspberry patch if the temperature is too high. The leaves will become yellow, and the canes will stop growing.
Raspberries need high humidity to prevent the fruit from drying out. The ideal humidity level for raspberries is between 90-95%. If the air is too dry, the raspberry will not develop properly. So, if you live in a dry climate, you may need to water your raspberry plants more often.
Raspberries need well-drained, sandy loam soil with a pH of 6.0-7.0. This pH range is optimal for plant growth. Soil that is too acidic or too alkaline can stunt the growth of raspberry plants. The soil should be rich in organic matter to retain moisture and nutrients.
If your raspberry has the proper environmental conditions, it should have no problem reaching its full potential height.
4. Unproportionate Fertilizer
Fertilizers can also affect the height of raspberry plants. Raspberries need nitrogen, phosphorus, and potassium for optimal growth and fruit production.
Raspberry plants need to be fertilized yearly to produce a good fruit crop. The best time to fertilize raspberries is in the spring, just before new growth begins.
Apply a balanced fertilizer, such as 10-10-10, at the rate of 1 pound per 100 square feet (435.6 pounds per acre) of garden area.
If you fertilize with too much nitrogen, they will produce excessive vegetative growth and fewer flowers. This can lead to fewer berries being produced.
Phosphorus is essential for water management and disease resistance, but too much phosphorus will encourage root growth and make the plant less resistant to drought.
Potassium is essential for water management and disease resistance, but a lot of potassium will make the plant more susceptible to disease.
And also, too much nitrogen can cause the raspberry plants to grow taller than usual. Using a fertilizer that is not proportionate can also cause the raspberry canes to grow taller. The right amount of fertilizer will help the raspberry canes grow to their usual height.
5. Lack of Pruning
Pruning is an integral part of raspberry cane maintenance. It helps to promote new growth and keeps the plant healthy. Pruning also helps to control the size of the plant. Not pruning raspberry plants can cause them to grow taller than usual.
To prune raspberry plants, cut out any canes over 2 years old. These canes will have produced fruit already and will not produce fruit again. Cut the canes back to the ground to encourage new growth.
Cutting out old canes will also help increase air circulation and reduce disease risk. Prune raspberry plants in the late winter or early spring before new growth begins.
If you don’t prune your raspberry plants, they will continue to grow taller and taller. Eventually, the canes will become so tall that they will fall over. Pruning is essential for keeping raspberry plants the right size.
How to Keep Raspberry Canes the Right Height
Keeping raspberry canes at the right height is essential for several reasons. Tall raspberry plants can fall over, making them difficult to harvest. Tall plants are also more susceptible to wind damage.
Luckily, there are several ways to keep raspberry plants at the right height:
1. Pruning
Pruning is the most common way to keep raspberry plants at the right height. When you prune, you remove some of the canes from the plant. This makes the plant smaller and more manageable.
Pruning also encourages lateral growth. This helps the plant produce more fruit. To prune, cut off the tips of the canes. You can also remove entire canes if necessary.
This should be done in the late winter or early spring.
2. Fertilizing Properly
Fertilizing raspberry plants properly can also help keep the height of your raspberries under control. Too much fertilizer can cause plants to grow too rapidly. This can make them leggy and weak.
Conversely, not enough fertilizer can slow down growth. This can result in stunted plants that are more susceptible to disease. The best way to fertilize raspberry plants is to use a balanced fertilizer.
3. Providing Support
If you live in an area with high winds, you may need to provide support for your raspberry plants. This can be done with staking or trellising.
Staking involves placing a support in the ground next to the plant.
Trellising is a bit more complicated. It involves training the canes to grow along a support structure. This is typically done with wire or string.
Both staking and trellising will help keep the plants upright. They will also make it easier to harvest the fruit, and it will control the plant to grow in a certain way. It may not grow as tall this way.
4. Attracting Bees for Pollination
Raspberries need to be pollinated by bees to set fruit. The fruit will not develop properly if the bees don’t pollinate the flowers. To ensure good pollination, plant raspberry plants in an area with plenty of bees.
You can also attract bees to your raspberry plants by planting other flowers nearby. Good pollinators for raspberries include borage, calendula, and cosmos. Poor pollination can cause raspberry plants to grow taller than they should.
This is because the plants are trying to compensate for the lack of fruit. Planting raspberries in an area with plenty of bees will help keep the plants at the right height and prevent them from becoming leggy.
Final Thoughts
Raspberry canes can grow quite tall, sometimes reaching over 6 feet (1.83 m) in height. This is due to a combination of factors, including the plant’s genetic makeup, the type of soil it is grown in, and the amount of sunlight it receives.
However, with proper care and attention, you can keep your raspberry canes under control and prevent them from getting too tall.
