Sweet, juicy raspberries (Rubus idaeus) are synonymous with the end of summer and early fall. Varieties of these hardy, fruit-bearing brambles can be found throughout much of the world, often thriving that they’re considered weeds.
The raspberry bush is a member of the rose family, sharing much of their growth cycle in common with cousins like strawberries, blackberries, and gooseberries.
This article explains the different raspberry plant growth stages for home gardeners, foragers, and anyone else interested in this tricky little cane fruit.
- Conditions for Growing Raspberries
- Raspberry Plant Growth Rate
- Growth Stages and Life Cycle of a Raspberry Bush
- When to Harvest Raspberries
- FAQs Raspberry Plant Growth Stages
Conditions for Growing Raspberries
Raspberries are perennial shrubs with a caning growth habit. The stems and leaves are pretty prickly (I can’t count the number of times my dog and I have gotten snagged up in a patch of wild raspberries while out walking!) but rarely as thorny as a regular rose bush.
These shrubs are incredibly adaptable. While traditional raspberries prefer cooler climates up to Hardiness Zone 3, newer cultivars can thrive in areas as far south as Zone 10.
You can grow raspberries in full sun or partial shade. Although raspberries tolerate shade better than most other fruits, plants will produce the best harvest with at least 6 hours of bright sunlight per day.
Raspberries have a reputation for being almost impossible to kill but are not entirely maintenance-free. Fruit-bearing canes only survive for two years. Annual pruning is a must to remove spent canes and encourage new, productive growth.
Raspberry Plant Growth Rate
The ultimate size of a raspberry bush depends on factors like genetics, soil quality, sunlight, and age. Most canes reach a height of 3 to 8 feet, which can be accomplished in a single year!
Growth Stages and Life Cycle of a Raspberry Bush
Raspberries are moderate-growing perennials with a somewhat unique life cycle. Each plant should produce fruit for at least 5 to 10 years, but individual canes only live for two years.
A raspberry cane will only put out leaves in its first year. It then flowers and fruits in its second year. New raspberry plants typically take 1 to 2 years to bear fruit, depending on how they are started (e.g., nursery transplants versus suckers).
1a. Seed Germination
Raspberry seeds can germinate, sprout, and produce new plants. However, raspberries are rarely started this way in cultivation.
Not only does this method take more time to produce harvestable fruit, but plants started from seed are not ‘true to type’. This means you have no way of knowing what quality of fruit will come from a plant grown from seed, even if the parent plant was a bonafide showstopper.
1b. Transplanting Suckers
Raspberry plants are more commonly grown from suckers. Raspberries naturally spread via their root systems. This is how wild raspberries form incredibly dense colonies that can choke out other plant life and be a nuisance in some areas.
A raspberry sucker forms from a specialized stem called a stolon (unsurprisingly, this is also how strawberries spread). Stolons grow from the crown or root system and produce new shoots and roots. You can dig up these offshoots and replant them as desired. You’ll usually find young raspberry suckers within 8 feet of a mature cane.
The main benefit of planting suckers is that they are genetic clones of the parent plant.
1c. Tip Layering
There’s one more way to propagate raspberries: tip layering. Canes will often bend down to touch the soil and produce new roots from the tip of the stem. You can take advantage of this natural adaptation by burying the tips of cut canes to encourage root development.
Like plants grown from suckers, raspberries started by tip layering will be clones of their parents.
2. Vegetative Growth
As I mentioned earlier, raspberries have short-lived canes. First-year growth is called a primocane. These canes start soft and green but develop a tough bark come winter. Second-year canes are then called floricanes. Floricanes will flower and bear fruit.
A healthy raspberry bush will send out new primocanes each year, which will then turn into floricanes and produce a harvest before dying off.
(Of course, nothing is ever cut and dry in the plant world. There are a few raspberry varieties that can produce fruit on both primocanes and floricanes.)
Flower bud production is triggered by cool temperatures and reduced daylight hours. By spring, your raspberry plant will already possess its flower buds for the year.
Most raspberries bloom in the summer months. The bloom period for any given plant can last several weeks.
The flowers of a raspberry must be pollinated to bear fruit. Fortunately, raspberries are self-fertile. This means you only need one flowering raspberry bush in the area to produce fruit.
Pollinating insects love the sweet nectar of raspberry blossoms. Bees are responsible for up to 95% of raspberry pollination.
Each raspberry flower contains dozens of separate ovaries that can be pollinated.
5. Fruit Production
It takes, on average, 30 days for the fruit to ripen after pollination. A single plant can produce 2 quarts of fruit or more per year.
A raspberry is an example of an aggregate fruit. Every ‘berry’ actually consists of 75 to 125 individual fruits called drupelets, according to New Mexico State University. Each drupelet develops from a different ovary and contains one seed.
When to Harvest Raspberries
One of the best ways to know when your raspberries will be ready for harvest is to watch the color of the fruit. In most varieties, yellow berries signal that ripening is just 4 to 5 days away. Raspberries won’t all ripen at the same time.
Ripe raspberries should be released from the stem with little effort. If you have to pull the fruit from the stem, the raspberries likely need another day to mature.
FAQs Raspberry Plant Growth Stages
Can you grow raspberries in pots?
Several varieties of raspberries grow well in pots or raised garden beds! This is an excellent option if you’re short on space, have poor-quality soil, or are worried about the canes spreading. I recommend sourcing a dwarf cultivar for the best results.
- New Mexico State University Raspberry Fruit Anatomy
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.