Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
The very first pie that I ever baked was made with raspberries that I foraged from a bush growing wild on campus when I was in college. Ever since then, I have wanted to grow raspberries.
What are Raspberries?
Raspberries (Rubus idaeus) are a biennial fruit bearing shrub that is related to roses. They are hardy in zones 3 – 9. There are cultivars that are native to Eurasia and North America. The name, raspberry, derives from two sources. One is the Germanic word raspoie which means thicket. Wild raspberry bushes grow in dense thickets. The other is the word raspise which was the name of a sweet wine that was similar in color to modern day rosée.
Raspberries have thorns like their rose cousins but unlike their rose cousins, the canes only live for two years. The roots are perennial. They push up canes called primocanes that grow and produce foliage the first year. The second year, the canes are known as floricanes and flower and bear fruit. The canes then die in the fall. They are replaced the following year by new primocanes. Depending on the cultivar, the canes can grow from 3 to 6 feet tall.
The floricanes bloom and bear fruit during the summer. Growers have developed new varieties of raspberries that bear fruit the first year and the second year. They are known as “everbearing”. The first year, they flower and bear fruit in the fall. The second year, they flower and bear fruit during the summer like traditional raspberries. The canes then die to be replaced the following spring with new canes which will bear fruit in the fall.
How to Grow Raspberries
Raspberries prefer to grow in full sun, but will tolerate light shade. In the shade, they will not bear as much fruit. The rule of thumb is that the more sun the shrubs get, the more berries they will have. They need rich, well-drained soil. Mix in some compost when you are planting.
Raspberries are usually planted in the early spring while they are still dormant. They can also be planted in the fall. This gives them a chance to establish their root system before going dormant for the winter. Most nurseries only sell raspberries in the spring so you may not have a choice about your planting time. Raspberry bushes should be planted 18 inches apart in rows that are 4 feet apart.
If you only have space for one bush, you can still grow raspberries. They are self-pollinating and don’t need another bush nearby to produce fruit.
Raspberries like to be moist. Make sure your shrubs are getting at least 1 inch of water each week. A thick layer of mulch will help retain moisture around your plants as well as prevent weeds from growing around them and competing for water.
Keep an eye out for suckers. Raspberries spread by sending out underground runners from which new canes, known as suckers, will grow. Always remove the suckers so that your shrubs can concentrate their energy on making fruit instead of new plants.
How to Harvest Raspberries
Once your shrub starts to bloom, keep a close eye on it. As soon as the flowers start to fade and berries start to form, cover the entire shrub with bird netting. Birds and squirrels love berries. They can easily strip away all of the berries before you have a chance to harvest any. Bird netting will prevent these pests from getting to your berries before you do.
Raspberries are not harvested according to their color. In fact, newer cultivars aren’t even red. The best way to tell if a berry is fully ripe is to gently tug on it. If it is fully ripe and ready for harvest, it should come away from the cane easily. If it is difficult to pick, it’s not ready.
How to Store Raspberries
Raspberries do not keep for very long. Plan to use them as soon as possible. They will keep in the refrigerator for only about 5 days. You can also freeze them for use later.
How to Prune Raspberries
Raspberries are easy to prune. The first year, you don’t have to prune. The second year, after they have bloomed and borne fruit, simply cut those second year canes to the ground. Your bush will grow new canes next spring. If you have shrubs that have a mix of primocanes (first year canes) and floricanes (second year canes), it’s easy to tell them apart so that you don’t prune the wrong ones. The primocanes are green. The floricanes are brown. Cut down the brown ones.
If you are growing the new everbearing raspberries that bloom and bear fruit their first year, you have two options. The first one is to allow your shrubs to bloom and bear fruit the first year in the fall and then allow those same canes to bloom and bear fruit the following summer before cutting them down.
Most gardeners don’t bother with the second year of fruit bearing. They simply cut down all of the canes in the fall after they have bloomed and borne fruit. New canes will grow in the spring which will bloom and bear fruit in fall.
How to Grow Raspberries From Stem Cuttings
The easiest way to propagate your raspberries is through stem cuttings. Stem cuttings work best because raspberries sucker very easily. All that you need to do is cut off one of the primocanes (first year canes) and stick it in the ground wherever you want a new raspberry bush to grow. Keep your cutting moist. New roots should start to grow in 2 to 4 weeks. You can tell that the cutting has roots if it is growing new leaves. Plants without roots cannot grow new foliage.
© 2019 Caren White
Demas W Jasper from Today's America and The World Beyond on May 29, 2020:
These are another of our favorites, along with raspberry jam! Thanks for the tips, and for the partial answer to my two questions on blackberries.
Tori Leumas on October 29, 2019:
I love raspberries. My grandparents have black raspberry bushes on their property.