Herbaceous Borders

Question 1

Creating and maintaining a herbaceous border

Answer 1

Site selection :
Full sun
Well drained soil
Sheltered from strong winds

Preparing the soil :
Remove perennial weeds & debris
Primary cultivations by either single or double digging (inverting the soil & breaking up clods) - best undertaken in autumn or spring

Incorporating of bulky organic matter e.g well rotted farmyard manure, gardeb compost, spent mushroom compost (check PH!)

Lime, sulphur, grit or sand could also be added at the cultivation stage.

Secondary cultivations by:
Levelling the soil
Consolidating the soil to remove large air pockets.
Applying fertiliser eg Growmore at a rate of 75g/m2 to 100g/m2
Creating a tilth by raking

Planning the border :

Most impact when planted in large patches of one particular plant

Drift of 3,5,7 (odd numbers work better) of one species.

Place plants still in their pots on the border.

Plan the border for
- long display of colour - as one plant fades from its season there is another one to take over.
- or for a burst of colour at a certain time
Different borders in the garden for different seasons

Know the characteristics of the plant
-compare to characteristics of neighbouring plants
-season of flowering
- ultimate height & spread
- foliage form
- flower colour

Generally Place tall plants at the back or centre of bed

Shorter plants at the front

Bring a few big ones forward a little to vary the contours

Maintain adequate plant spacings - check labels and don’t plant too close together. Space so that plants get to full spread before touching each other - or plant closer & thin out later (costs more money)

When to plant?
Spring (early March to early May)
Or
Autumn (late Sept to Oct) while the ground is moist.

Barerooted plants - these need to planted in the optimum times, mentioned before. Usually bought by mail-order.

Container-grown plants - sold throughout the year at garden centres & nurseries. They can be planted any time as long as ground isn’t frozen or waterlogged. Likewise, after planting, they must be kept moist, especially if planted in summer.

Planting -
1. bare root herbaceous perennials -

Ensure plants are soaked well before planting to ensure they’re well hydrated

Use a trowel or spade to create a hole just deep & wide enough to set in the clump. The aim is to bury just the roots, leaving the bases of the stems (when in growth in summer) & / or the shoots (in spring) above ground

Firm back the soil, using your hand for small clumps and your heel on large ones

Water in well - even if the ground is moist and rain is forecast. This will settle the soil and prevent desiccation.

2. Planting plant container grown herbaceous perennials -

Weeding :
Hand weeding. Carried out during the growing season / spring and summer months using a hoe of garden fork. Seedling annual weeds can be left on the surface after removal to shrivel and die while perennial weeds need to be dug out including their roots and removed. It may be necessary to dig up the herbaceous perennial to remove the perennial weed and then replant it.

Mulching:
Can be carried out once all weeds have been removed using well rotted garden compost or composted leaves to a depth of 50-75mm during early autumn or spring. Bark is less suitable as a mulch for herbaceous perennials as some species e.g Asters are surface rooting and will thrive better in garden compost.

Chemical: Diquat which is a contact herbicide can be used to control annual weeds and glyphosate, which is a translocatec herbicide can be used for perennial weeds.
Glyphosate can be obtained in a gel form which can be painted on the leaves of perennial weeds or as a spray for weeds eg Calystegia deployment which have been allowed to grow up a cane for easier control.

PLANTING DEPTHS:

Shallow planting -
Crown slightly above ground level
Sisyrinchium striatum
Dianthus (pinks)
Phormiums
Iris

Ground level -
Crown at ground level
Most perennials should be planted this way. If too deep the crown can rot.

Below ground -
Crown about 2cm below ground level
Hostas, Dicentra, Peony, Convallaria

Deep planting -
Crown about 10cm below the surface
Polygonatum, Aconitum, Crocosmia, Alstromeria

MAINTENANCE OF HERBACIOUS PLANTS …
- watering in dry weather

• feeding in April & June
• Remove faded flowers unless heads are decorating or seeds are required. Cut stem back to a side shoot l, encourages another flush of flowers -
  Chrysanthemum, Dianthus, Lupins, Mimulus, Penstemons, Phlox.
• Encourage new growth: cut back old stems to ground level as new shoots are growing at the base. May produce 2nd flush of flowers - Nepeta, Delphiniums, Geraniums, Salvias.
• for better flowers think out young shoots when they’re 1/3rd of their final height. Remove about 1 in 3 by cutting out the weakest at the base. Phlox, Asters, Lupins, Delphiuim, Solidago.
• Bushy plants: pinch out when shoots 1/3 of final height, about 2.5-5cm just above a leaf joint. Aster, Chrysanthemums, Phlox, Rudebekia
• Tidying up plants: cut down decaying foliage and dead stems to base.
• when plants are tidied place a cane and label to identify plant spot when died back. Prevents disturbance by digging over.
• Stalking: The use of Betula or Corylus sticks which are positioned as the plant is coming in to growth in the spring ensuring that minimal damage is made to the crown of the plant and its roots. The plant whose foliage hides the support is supported by growing through it.
• Individual flowerheads of plants e.g. delphiniums can be staked using bamboo canes. The canes are obscured by the flower and are tied in using discreet coloured biodegradable twine.
• vegetative propagation : seeds, division & stem, root, runner or basal cuttings

Maintain plant health by monitoring for PESTS & DISEASES and reacting accordingly

• Slugs & snails :
  Can be controlled by using beef traps, removing them by hand and by using nematodes & molliscicides
• Vine weevils :
  Can be controlled by the use of a single parasitic nematode such as Steinernema krausii & physically hand picking the larvae & adults
• Aphids :
  Can be controlled by the use of chemicals e.g. Fatty acids, blasting them with jets of water and encouraging naturally occurring predators eg. Ladybirds by providing a suitable habitat for them.