Tuesday, 28 March 2017

Different types of roots + what is the difference between bulbs, corms, tubers and rhizomes.

The Root

What is the function of a root:

  • Absorption of water and nutrients through the root hairs.
  • Anchoring the plant into the soil to support it.
  • Storage of food and nutrients.
  • Synthesis of specific components (nicotine).
Parts of a root:

  • Primary root, not dominant, the whole root is a system of fibres and branches.
  • Lateral roots.
  • Root hairs.
  • Root tip.
  • Root cap.
Types of root:
  • Primary root with lateral roots (Geranium).

  • Taproot (Carrot).
  • Fibrous root (Leek).

  • Tuber (Potatoes).

  • Aerial roots(Ivy).

  • Tuberous root (Dahlia).

  • Haustoria root (Mistletoe).

  • Runners or Stolons (Strawberry) - Stolons are horizontal stems that run above ground and produce new clone plants spaced at various intervals.

True Bulbs - Daffodil, Tulips, Hyacinth, Snowdrop. Lily.

  • Most have a papery skin (tunic) on the outside, to prevent the bulb from drying out. Lilies do not have a papery skin and therefore dry out faster and are more easily bruised.
  • They are more or less rounded and narrow to a point on the top.
  • They have a flat part called a basal plate at the bottom. The roots grow from the basal plate as well as the shoots and scales.
  • True bulbs have new bulbs (offsets which form from the basal plate).
  • They are made up of rings called 'scales', which are modified leaves that store food.
  • True bulbs add rings each year from the inside, outside rings are used up.

Daffodil blindness

A number of causes can be to blame for daffodil blindness;

Dry situation: In a dry place, or in drought conditions, daffodils may die down prematurely. After flowering, growth should normally continue for several weeks, allowing food reserves in the bulb to be replenished before the following season's flower buds are formed. If growth stops prematurely the bulb may, due to lack of food reserves, fail to form a flower bud.

Defoliation: Leaves removed soon after flowering by mowing or when tidying up the garden can lead to blindness. As with dryness it prevents the bulb building up food reserves for the future.

Knotting: Gardeners often tidy up clumps of daffodils after flowering by drawing the leaves together into a knot. This is not recommended as it reduces their ability to function and may cause or increase the risk of blindness.

Seeding: Allowing seed capsules to form after flowering means that energy is diverted from the process of bulb rebuilding.

Nutrition: Good quality and newly purchased bulbs will normally flower well in their first year on any kind of soil, but in poorer light soils performance may rapidly decline without some additional nutrition.

Planting depth: Shallow planting encourages bulbs to divide, producing lots of bulbs too small to flower.  Plant bulbs 2 to 4 x their depth.

Planting time: Bulb performance can rapidly decline if bulbs are planted later than mid-September.

Overcrowding: After a few years, clumps of daffodils may become overcrowded leading to poor flowering.

Pests: Narcissus bulb fly and narcissus eelworm may damage bulbs leading to poor flowering.

Diseases: Diseases such as narcissus basal rot or daffodil viruses may cause bulbs to die or decline in vigour and flowering

Corms - Crocosmia, Gladioli, Freesia, Crocus.

  • Corms have a papery skin (tunic) and a basal plate at the bottom and 1 or more growing points at the top.
  • They are uniform from the inside and do not have rings.
  • Corms are stem tissue, modified and developed to store food.
  • They are used up for growing the flower before it withers away and has formed 1 or more new corms. The new corm contains the food reserve for the dormant crocus.
Tubers - Potatoes, Tuberous Begonia, Cyclamen, Anemones.

  • Tubers have no papery skin (tunic).
  • They have not basal plate, most root from the bottom.
  • They have several growing points called 'eyes'.
  • With some tubers like Anemones it is difficult to find the growing points.  With them it is best to plant them sideways.
Tuberous roots - Dahlias, Daylilies, Sweet potatoes.

  • They are modified, enlarged, specialised roots that store food. They are used up during the growing season to be replaced by new storage units.
  • They cluster together, joined to the bottom of a stem. The stem contains the new growing point for the next year - a piece of root alone won't grow.

Rhizomes - Iris, Lily of the Valley, Canna, Ginger.

  • Rhizomes branch out and each new portion develops roots and a shoot of itw own.

How to divide plants:

Lots of perennial plants can be divided, however the plant should have a root ball, plants that spread from a central crown and have a clumping growth habit.

Plants with a taproot are propagated through cuttings and seeds.

When to divide garden plants:

Plants are divided in early spring or autumn, normally spring and summer flowering plants are divided in autumn and the others are divided in spring.

Dividing the plants:

After some years a perennial start showing signes of aging.  The central part of the clump is not longer producing flowers.
  1. Dig up the entire clump carefully so not to damage the roots. Shake off the excess soil.
  2. Separate the plant by chopping through the crown with a spade.
  3. Divide the plant into smaller pieces by hand, retaining only the healthy sections and discard the old centre bit.
  4. Trim the top, make sure the root section is larger than the top of the plant.
  5. Take the opportunity if you want to replant the perennial in the same spot by cleaning and fertilising the area before replanting or plant them out in a different spot.

Dividing fibrous roots:
  • When a plant is difficult to separate, for instance with fibrous roots, use two forks, back-to-back and tear the plant apart.

Dividing fleshy rootstock:
  • With plant like Agapanthus or Hosta, cut the plant with a spade into sections, may sure that each section has a shoot or eye.

Dividing rhizomes like rhizomatous Iris or Bergenia:
  1. Lift the plant with a fork, making sure you enter the fork into the earth well away from the rhizomes to avoid damaging them. 
  2. Shake the plant to remove excess soil, split into managing pieces by hand.
  3. Discard the old rhizomes and cut the rest into small new clumps making sure they have roots and a shoot or eye.  
  4. Trim off the old, excess root.
  5. Trim of long shoots and with an Iris cut the leaves into a mitre shape about 15 cm tall.Plant the rhizomes 15 cm apart.  
  6. The rhizomes should be half buried, with their leaves and buds upright. Firm in and water well.

Bibliography:  RHS Encyclopedia of Gardening; Website - Gardening Know How, Dividing Plants; National Gardening Association - What are bulbs, corms, tubers and rhizomes.
Photos:  Web

Wednesday, 8 March 2017

Garden Group Meeting - 28 February 2017 - Video of Highgrove

Sue visited Highgrove, Prince Charles' garden, last summer. She was very impressed.  Subsequently she came across a video on U-tube about the garden. For those members who were not able to see it, the video link is:


Friday, 3 February 2017

Caterpillars - Buxus sempervirens

The following we received from Dominique Urban:

How to protect and treat Box (Buxus)

The plants are attacked by an insect, “pyralis” (Fr : pyrale). (or meal moth, eastern firefly and big dipper firefly)

They can be protected and treated by spraying products against  la pyrale du bois” or “la pyrale
du chou” (the same product for both).

The caterpillar that does all the damage

If you prefer to use organic sprays, there is one called “Solabiol” which is available at Racine in Draguignan and probably other places.

Box ravaged by the caterpillar

Asian Hornets - the damage they do - how to eliminate them

Dominique Urban made us aware of the damage the Asian Hornet is causing in France.  The following is her input:

Eliminating the Asian Hornets (Fr : “frelons asiatiques”)

These hornets, recently arrived in our part of the country from Asia, feed on bees. They stay near
the beehives and catch them on their way in or out of the hives.

The damage to the bee population is enormous, specially as when this damage is added to that caused by weedkillers. Some beekeepers have lost most of their bees.

There is a very simple solution to eliminate many female frelons and thus significantly reduce, year after year, their total numbers :

In Spring, the female frelon looks for sugary food necessary to prepare her eggs (she lays about a thousand!), and still keeps looking for it when it becomes carnivorous.   So we can lay the frelon traps from the end of February to the end of Summer.

You can either buy a wasp trap and hang it from a branch, not too high, and fill it with the kind of
product shown on the photo or, if you like DIY, you can make one from two plastic bottles, one with a large neck at the base of the trap inserted inside the bottom of the other one (used as a tunnel bringing the hornets in).

For the liquid, you can use anything sugary such as water with jam or sugar, or beer…

If there are hornets’ nests near your garden, you’ll capture enormous quantities :  in our fairly small
garden we catch more than 300 with three traps each year !  We never see them in the wild and would never have thought there was a problem !   If you are in a place where the frelons haven’t yet arrived, you’ll catch wasps and big black flies . . . . . so the traps are multi-purpose !

If you like honey and think that bees are necessary for the human race to survive, put up your traps

now !

Asiatic Hornet's Hive

Thursday, 2 February 2017

How to make an organic pest-repellent plant spray

Tineke Stoffels mentioned this plant spray on our last garden group meeting.  She has used this spray  last summer, it was very effective against lice and spider mite.  She even sprayed her Buxus with the mixture and had no problems with the small caterpillars that devour the Buxus before you realise they are there.

The recipe below mentions a blender, no need, she chops up the ingredients and puts it into a used plastic milk bottle, adds the water and screws on the top. She leaves it to marinate for at least 24 hours.  After straining the mixture, Tineke adds a dash of washing up liquid, she finds the spray clings better to the plant.

How to Make Onion Juice for Plant Spray

A blender offers a convenient means to puree onions and other spray ingredients.

Garden crops and ornamental plants throughout the landscape are potentially bothered by many different types of destructive pests. Rather than rely solely on commercially available or synthetic pest control products, you may opt to create your own pest-repelling plant spray. One potential effective ingredient in a homemade pest spray is onion, which has a strong odor offensive to many pests. Combining an onion with garlic and pepper to make a spray further increase its effectiveness against pests that chew on plant leaves or suck out plant fluids./

  • Blend about six cloves of garlic, one large onion and a tablespoon of cayenne pepper or two whole peppers together in a blender or food processor.
  • Combine the blended onion, garlic and pepper with a litre of water and let the mixture sit in a refrigerator for at least 24 hours.
  • Pour the mixture through a strainer or cheesecloth into a jar to separate the solid mash from the liquid.
  • Bury the separated solids shallowly in areas of your garden or yard near plants that are particularly bothered by pests.
  • Pour the onion solution into a spray bottle
  • Spray pest-infested or vulnerable plants thoroughly with the onion spray.
  • Store any unused spray in the refrigerator. Use it within two weeks, spraying the plants every few days and following any rainfall or overhead irrigation.

Things You Will Need:

Garlic cloves (at least six)
Large onion
Cayenne powder or one or two peppers
Strainer or cheesecloth
Spray bottle
Biodegradable dish soap


Add about a tablespoon of biodegradable dishwashing liquid to the already-steeped spray solution to increase its effectiveness against certain pests.

Test any homemade pest spray on a few leaves in an inconspicuous part of the plant and monitor these leaves for any injury caused by the spray for a day or two before treating the entire plant.


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