Gardeners Tips

When a plants roots fill the pot then it is time to think about repotting. Compost breaks down overtime, becomes prone to waterlogging and is less aerated. Plants in John Innes No.3 compost will last a bit longer but repotting every couple of years may still be needed to retain vigour.

 Why Repot

• Repotting helps consistency of watering. You are less likely to get waterlogging or dry compacted roots that are hard to water.
• New compost and nutrient is made available to your plants.
• Cramped roots will stunt the plants ability to perform above ground.
• Tip for bulbs like Eucomis- Pot up in black plastic pots, then place inside a decorative pot in summer.

How to Repot

• Early spring is a good time to do your repotting.
• Gently ease out the root ball whilst supporting the plant.
• Tease out some compost (upto a third) from the top and bottom and free any roots that are growing round and round the pot edges.
• Lightly trim the roots from around the edges. If they are very tightly packed slice off a good sliver from one side.
• Select a slightly larger pot, place the plant in the centre at the same depth and fill in the sides with fresh compost. Push compost down to avoid air pockets.
• Add some slow release fertiliser granules as you repot and push some into the old root ball.
• In years when you do not repot, top dress the pot with fresh compost by scraping away the top 2″ and adding fresh compost.
• An over-potted plant will focus on root growth at the expense of new foliage and flowers.
• Water the repotted plant and if the compost sinks top up or add gravel as a top mulch.

Root Pruning

• Lay plants on a plastic sheet and tease out the roots removing a few inches of the compost from around the rootball.
• Avoid damage to the main root and check for pests.
• Lightly trim the fine hairy roots to restrict excess growth after repotting.

Aftercare

• After repotting drench the rootball and soil.
• Allow the soil to start drying before watering again
• Subsequently water little and often feeding regularly when the plant is in active growth.
• When new growth starts and the plant is re-established in the pot pinch back new shoots or trim as appropriate

Repotting House Plants

• The process is very similar to other repotting.
• It may be obvious that a plant needs repotting when roots grow out of the hole in the bottom of the pot.
• Water the plant before you take it out of its current pot and let it stand for a couple of hours.
• Once repotted do not feed for 6-8 weeks as the compost should provide new nutrients.
• Keep your tools and pots clean and sterile particularly for Orchids.
• Use appropriate special purpose composts for Citrus trees, bonsai, African Violets, Orchids etc.

What is a Potbound Plant

• A plant that has been in a pot or container long enough to fill the pot with roots can be said to be potbound.
• Roots often twist around the outer edge of the pot and form a knotty clump of roots.
• The roots may be so tight that a plastic pot bulges and has to be cut away with secateurs to get the plant out.
• A terracotta pot that has become pot bound may need to be broken to access the plant.
• Houseplants that can’t take up water, have roots coming out of drainage holes and a hard impenetrable surface are likely to be pot bound

Problems Caused by being Potbound

• The compost and nutrient is all consumed and used up.
• It is almost impossible to water and get the centre of the root ball damp. The roots may be trapped in dry compost
• Top growth and general health will be restricted where a plant suffers from being potbound.

Cures for Potbound Problems

• You can surgically remove some of the twisted roots on many potbound plants including shrubs and herbaceous plants.
• One third of the roots can be removed comfortably. The old thick, brown and damaged roots should go first.
• Aim to create space for new roots to develop.
• Fleshy rooted plants and those that dislike root disturbance such as Alstroemeria and Peonies should have their roots left whole.
• Open up roots by gently tweaking the edges and shaking out some compost to open up the root ball.
• Allow the root ball to soak for at least an hour
• If planting out dig a large hole and lay the tweaked out roots as widely as possible. Do not leave the root as a ball or the they will never spread into the surrounding ground as you intend.
• If repotting your plant shake off as much old compost as possible, plant in a larger container and do not leave it too long to repot in the future.

Opposite of Potbound

• Some garden centres put plants in larger pots for sale so they can charge more for them.
• Without time for the plant to develop roots in the new pot it may be immature and quite unsuitable.
• This may mean the ball of compost falls away when you get the plant ready for its new home. I think this is just sharp practice.
• Over potting is putting a plant in a pot far too large. At the most use a pot that is double the size of the existing pot for even distribution of nutrient and moisture.

Attribution ‘The root of the problem Project 365(2) Day 111’ by Keith Williamson, on Flickr Creative Commons License Deed Attribution 2.0 Generic (CC BY 2.0)

Roots by billy liar, on Flickr (CC BY 2.0)

Divide and rule is the motto for those who wish to be king of the herbaceous garden. More plants for some little effort.

Offsets and Crowns

One of my favourite jobs is growing more primroses, primulas and polyanthus. Probably more than my garden wants or needs but as I have said before I am a quantity man not necessarily a quality gardener.
After flowering, primulas produce baby plants as a means of propagating the species in addition to seeding. Virtually each of the flowers on this primula denticula has its own new plantlet.
On a damp day I dig up clumps of Primula and tease away the roots from each new crown. Sometimes the original plant has become old and frail but more often than not it can go back into the ground refreshed and renewed to grow again for next year.

Runners and Stolon

Strawberry plants produce growths that resemble floppy stalks with leaves growing at regular intervals. These stalks lay on the ground and the leaves are tempted into rooting – several on each length. Pot these rooted runners or encourage permanent residence in the strawberry bed by planting the roots and severing them from the main plant at the same time. The best plants will be on the part of the runner nearest the host plant and you only want to take 3/4 plantlets from each host.
To protect a young strawberry plant in the first couple of season cut off the runners as soon as they appear to allow strength to be built up.
Mint and Bergenia are among other plants that can be propagated by stolon which are similar to strawberry runners.

Clump Division

Many herbaceous plants form progressively larger clumps of root.
Older Hostas can have a solid root and crown mass that can best be divided by chopping into parts with a spade.
The slice with a spade method is how I deal with Day Lilies. The only thing to worry about is ensuring several buds or eyes are left on eack resultant cutting (or should it be clumping).
Ornamental grasses and bamboos lend themselves to root division in early spring. For Pampas grass you may need a spade or even a saw but most can be pulled apart.

More Herbaceous Propagation

Adventurous roots are those that wander off above or below soil level. They can often be used to grow new plants.
Several plants such as delphiniums and oriental poppies can be propagated from pieces of root as root cuttings.
Simple stem cuttings can be potted up in September when cutting back your plants. Often this will result in lots more plants.
Offsets are similar to runners and are often found on Sempervivum house leeks.

Houseplant Propagation

Leaf cuttings are a popular way of propagating African violets and Streptocarpus
Offsets are able to root and make new plants from Aloe and Agave

Photo credits
P1030686 by jessicareeder CC BY 2.0