Last Updated on October 31, 2021 by Phil
Want to keep your favorite plants forever? Here’s how to divide perennials.
As beautiful as perennials are, they age. And, after a few seasons, some can die, get damaged or start to clump. Dividing your perennials is a great way to help keep them healthy. It also improves their ability to bloom, not to mention their longevity.
Of course, you also get to grow more of your favorite perennials for free. That way, in case something happens to the parent plant, you’ll still have a backup.
Here’s everything you need to know about dividing perennials.
Why Divide Perennials?
The most common reason for dividing perennials is to grow more plants. This is a simple method of adding more plants to your collection or garden. It is also free.
The best time to divide perennials is during spring so that it can quickly recover and start growing again.
Additionally, another reason why many plant owners divide perennials is to control their size. This often applies to larger plants especially indoors. Although, you may want to limit the space a plant takes up in the garden as well.
Dividing them will let you keep the plant in the same container instead of having to repot it into a larger one.
Finally, for plants that have outgrown their containers or space allotted to them in the garden, division helps reduce crowding. This helps because plants in crowded spaces will end up competing for water and nutrients.
In pots, they won’t get enough water or nutrients either since there’s too little space (soil) left. As such, you’ll notice the soil dry up very quickly even if you water like you normally would.
As such, dividing them will help stimulate new growth.
Improved air circulation and more space for roots to grow are other side bonuses that benefit the plant as well.
When is the Best Time to Divide Perennials?
A general answer to this question would be spring. That’s because spring is when most plants will start to actively grow. As such, this will let the new plants grow quickly after they’re planted.
However, not all plants are the same.
As such, the answer to the question becomes more complicated. Also, there are other issues that can come into play which I’ll discuss below.
So, the long answer is, it depends on the type of plant.
Here are a few basic rules.
- Don’t divide a plant that is currently blooming. During this time, it will focus on flowering as such, you won’t want to interrupt it. Avoiding this period will allow the plant to focus on regenerating its roots and leaves.
- Don’t divide a sick plant. This applies to overwatered plants, those with pests, diseases and other issues. You want to focus on fixing the current problem before dividing it. otherwise you could end up with multiple dead plants.
- Divide a plant when it is strong and healthy. In contrast, you want the plant to be in its best conditions before you divide since division requires taking the plant out of its home, be it the ground or container. This causes shock and stress that the plant needs to overcome.
- Divide when it has outgrown its pot. Division is a great way to reduce the size of the parent plant as well so you don’t need to move it to a larger container. This also lets you limit the size in case it gets too big for your living room.
- Avoid very hot or very cold weather. The best time to divide the plant is during moderate to cool weather. Division involves taking out the plant from its home, be it a pot or the ground, then cutting it into segments (and wounding it) then replanting. This process causes shock and requires recovery. Overly hot or cold temperature only adds to the stress.
The next thing to consider is when the perennial will bloom. This will give you a clue on when the best time to divide it.
- For perennials that bloom in spring or summer – Divide in the Fall
- For perennials that bloom in the fall – Divide in the Spring
How to Divide Perennials
Now for the fun part, dividing your perennials. Before you do, it is important to prepare them for the process.
Preparing for Division
Step one is to prepare the perennials for division. This is important because the division process causes stress and shock to plants.
As such, don’t be surprised that some plants don’t grow immediately after you’ve divided them. I’ve had a few instances where the divided plant too as long as 2 weeks to recover before beginning to grow again.
So, be patient.
I’ve found that saturating the plant for the day before you divide it gives it enough hydration. Because dividing the plant interrupts it feeding and drinking process, well-saturated roots will help reduce the stress it experiences.
Another thing you can do to help the roots is to trim foliage if there’s a lot of it. The more top growth there is, the more work the roots will need to do to try to keep the foliage healthy. This adds to the stress it will experience.
But, don’t over prune it. Limit the amount of pruning to at most a third of the leaves.
Where Should You Place the Divided Plants
Location, location, location.
This is the next thing you want to plan out.
- For garden plants, it is a good idea to find a good spot where the new plant will go. You can also take this opportunity to move the parent plant. I like to dig the holes before taking the root ball out of the ground. This way you can immediately move and plant the divided segments. All the basic rules will apply here. These include, choosing a spot with enough room for its roots and foliage to extend and grow. Pick a spot with ample sunlight depending on the kind of plant you’re dividing. Also, avoid placing it near large trees or shrubs that have deep, strong, extensive roots. Often, your perennial will lose when competing for water and nutrients against these larger plants.
- For container plants, prepare the appropriate number of pots. This will depend on how many segments you plan on dividing the plant. Make sure that each pot has drainage holes. You can return the parent plant to its original container. Additionally, have enough potting mix ready to go. The kind of potting soil you use will depend on what plant you’re dealing with. Finally, choose the spot where each container will end up staying.
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How to Divide Perennials Step by Step
Now that the preliminary things are out of the way, it is time to divide perennials.
If you’re like me, you probably prefer watching the process than reading about it. So, here’s a great video that shows you how to divide perennials.
It also explains the different types of perennials and how to divide each
Dividing Perennials Step by Step
- Start by digging up the plant. I like to keep my distance away from the stems when digging. This way you don’t accidentally damage the roots with the shovel.
- Once the plant is out, check the root ball for any issues. You want healthy roots. Look out for mushy, dark colored roots which is a sign of problems. If you do find them, trim them off. Hopefully, there are none or only few (if they’re present). If there are too many damaged roots, it will be difficult to rescue the plant.
- Next, loosen the roots so they don’t curl around one another or the root ball. Then, remove excess soil to expose more of the roots. The more visible the ends are the better you’ll be able to plan out where you’ll be dividing the segments.
- Pick out the segments you want to divided. The bigger the plant, the more divisions you can make. However, if you want, you can just make one cut so you end up with the mother plant and a new plant. This is really up to you.
- Use a knife or saw to separate the sections. Make sure to sterilize the blade before cutting. You can use rubbing alcohol on the blade to sanitize it. Ideally, you want to pick out healthy sections to give them the best chance to grow into their own plants.
- Another tip when dividing, make sure that each section will have enough roots as well as healthy leaves. You don’t want the new plant to be too small or sorry looking.
- Once you’ve divided the plant, it is time to prepare the soil where you’ll be planting it. It is a good idea to amend the soil to give it the right pH that’s suitable for the plant. Using compost also helps a lot as it improves soil structure, adds nutrients and organic matter to the soil.
- Place the mother plant back into its original area. Or, you can place it in a new spot with amended soil as well. Another option is to move it to a container if you wish.
- Next plant the divided section/s. I like to prepare the new plots by digging before I divide the perennial. This way, the holes into which they’ll go in are ready once you’ve separated them from the mother plant.
- Now it is time to add starter fertilizer. Make sure to apply this when you water to make sure that the concentration is not too high. Too much fertilizer does more harm than good to your plants.
- Finally, it is time to enjoy and wait. Once the plants recover from the shock of division, they will start growing quickly.
You can follow the same steps when dividing perennials in containers. The only difference is that instead of digging up the root ball from the ground, you’ll be taking it out of the container. This makes it easier with less manual labor involved.
Also, instead of digging new holes to place the divided sections, you’ll need one or more pots. The pots will be smaller than the one for the parent plant’s. But, they should have drainage holes.
The other important difference is you need to prepare potting soil. You can buy a commercial potting mix or make your own DIY potting mix. Don’t use garden soil as it can contain pathogens and weed seeds.
Finally, plant the divided segments into their individual pots and place them where they get enough sunlight.
Learning how to divide perennials allows you to grow new plants at no cost. This way you can enjoy more of your favorite plants without having to go to the garden center and buy new plants.
By following the detailed steps above, you’ll be able to quickly learn to divide different kinds of perennials in your garden or in containers.