There are two main requirements for attracting beneficial insects (pollinators and predators) to your garden and they are the same for attracting any guest – food and accommodation. Yes, there are a few other little management issues, but food and accommodation are the biggies. While accommodation is addressed elsewhere, this article mainly looks at the food angle – providing an insectary (insect attracting) flower bed.
A great many beneficial insects make use of flowers and the nectar they provide as a food source. Some have long mouthparts for extracting it from deep flowers while others have short mouthparts and need more accessible nectar supplies. To provide the variety of species required, some planning needs to be done. The planning needs to take into account when the plants can be sown and when they will flower so you can be sure you have the right species.
Species Selection
When working out which species of flowering plants you want to build into your insectary beds, there are some questions that are worth thinking about –
Do they do well in my area/climate? – OK this is an obvious one but making sure at the outset that all flowering plants you put in are adaptable to your area and growing conditions will save lots of frustration in the long run.
How long with they take to flower and how long will they flower for? The quicker the plants get to flowering stage the quicker they can start attracting those helpful little insects! Also, the longer the flowering period the less hassle you will have setting up your beds so that they will be providing blossom year round.
What colour blossom will they produce? A variety of colours is good, not just from an aesthetic point of view but different colours attract different species, for example wasps prefer yellow and white flowers while the pollinators prefer blue flowers but a variety ensures there is something there for all of the beneficial insects.
Will they self-seed and naturalise and do they have potential to become a weed? Having species which will naturalise in your garden is good, it means that they will require less care and attention to keep them going. A species which is too freely seeding or where the seed can easily be dispersed by birds or the wind can cause problems, however. If you live near a national park this can be of particular concern so that garden escapes into the bush can be prevented.
How hardy are they? Again, a plant which is hardy will prove to be a lot less work and will have a better chance of establishment than plants which are drought or frost sensitive.
Do they fit in with existing plantings? If you are not starting your garden from scratch but are looking to integrate the new species into existing plantings, they will need to fit in with what you are already growing. A bed of colourful annuals may look out of place in a native garden, dryland garden or a garden consisting mostly of trees. On the other hand if you are like me and don’t really care, it won’t be an issue.
Can they perform multiple roles? There is no reason why plants put into your garden to attract beneficial insects can’t perform other roles as well.
- Flowers which attract insects can also be edible (eg nasturtiums or calendulas) and
- Flowering herbs such as borage, lavender and lemon balm can add delightful fragrances and be used in cooking or medicinally as well.
- Leaving vegetable to flower such as umbellifers (carrots, parsnips) or brassicas (broccoli or kale) provides you with a feed from the original plantings and then attracts beneficial insects as well.
- Nitrogen fixers such as Lucerne, white clover or red clover improve the fertility of your plantings as well as attracting beneficial insects.
- Dynamic accumulators are plants which delve down deep into the soil to bring up nutrients which are out of reach of most plants, their leaves then being used as mulch. Comfrey and dandelion are both plants which have this action but also attract beneficial insects with their flowers.
- Fruiting plants such as apples, avocadoes, olives and passionfruit attract beneficial insects with their flowers and give you a harvest of fruit as a bonus.
- Windbreak plants are planted on the side of your property which is subject to the prevailing winds to protect more sensitive plants form the strong winds coming from that direction. Natives such as bottlebrush (callistemon) and acacias can do double duty as windbreaks and insect attractors.
- Ground covers are used to act as a living mulch and to turn bare areas of bed into productive areas, but they can also attract beneficial insects. Such groundcovers include vetch and sweet alyssum.
Indeed some plants can do triple duty – vetch is a nitrogen fixer as well as ground cover and insect attractant, nasturtium is a ground cover as well as having edible flowers and attracting insects and so forth. A little research before you select your species and you can get the most out of your productive insectary garden.
Other Management Issues
I mentioned earlier that there are a number of other management issues to be considered when designing the insectary area, and these are much easier to deal with at the planning stage.
Clumps rather than single plantings – insects are attracted to clumps of flowering insectary plants rather than single specimen plants, so planning to plant in clumps makes sense.
Don’t use pesticides – This goes without saying! Any broad spectrum pesticide, even those organic ones like chilli and garlic spray can have a bad impact on non-target organisms. The organic ones will not persist in the environment but while they are active it will be bad news for pollinators and predator insects alike. Spraying with any kind of pesticide should be the action of last resort to treat an infestation when all else fails.
Reduce digging – There are a number of bad things which come from digging in the soil including damaging the soil structure and allowing organic matter to be oxidised out, but it can also be devastating for the life in the soil – the soil biota. In this case not digging in the soil prevents damage to predator eggs and nymphs living in the soil, which will then emerge and come to your aid later in the year.
Provide water – All living organisms need water at some stage in their life cycle and some predators such as dragonflies reproduce in it so it is worth having some source of water in or near your insectary area. It is also worth having a piece of wood or some other material so that insects can is it as a platform to drink from and climb out of the water container so they don’t drown. A pile of gravel extending above the water line will also help to prevent insects drowning while trying to get a drink.
Developing a Blossom Calendar
To ensure that you have year ‘round blossom to feed your beneficial insects it is worth drawing up a flower or blossom calendar. The idea is, as you research the plants you want to use, find out when they flower and plot it on a month-by-month 12 month calendar. Then it becomes a simple matter to work out if you have the whole year covered or not.
To develop my insectary blossom calendar I searched around for existing “beneficial insect” attracting seed mixes for sale on the net and consulted books like Penny Woodward’s Pest Repellent Plants. I used this information to develop a list of species which would not only attract beneficial insects and be able to provide other functions as well, but also fit into my climate and garden. Once I had worked out a list of plants which looked promising I then researched their other properties, when they bloomed, when to sow them and whether they were annuals or perennials and put it all down on the blossom calendar.
While I recommend developing a blossom calendar for you unique situation, you can use the one I put together as a starting point. It and a blank calendar form can be downloaded here.
Using the Calendar
I used the calendar to develop up a list of plants with which to start my insectary bed. For a start they needed to be able to be sown in autumn, because that’s where we are now and I didn’t want to put this off until spring so that limited the number of species I could use. I also wanted at least one ground cover, a nitrogen fixer and a collection of different edible and cut flowers which would bloom the year round. After much deliberation, I came up with the following list –
Alyssum – scented, edible flowers and a long blooming period
Coreopsis – scented edible flowers which will start blooming in spring
Dill – edible herb
Gypsophila – edible and cut flower, ready to bloom in spring
Lupins – nitrogen fixer, edible blooms and seed,
Marguerite Daisy – winter flowering cut flower
Mustard – dynamic accumulator, edible plant and seeds
Queen Anne’s Lace – edible root and flower
White clover – ground cover, nitrogen fixer
I should also include the choko and orange tree as these are already in the area and growing. Together these will form the basis of my multifunctional insectary bed.
Using all of this information I then drew up a plan as to how things will go together, which is available here. Of course the plan may need to be changed if unexpected issues crop up during the implementation phase.
And so the next part will be putting it all into practice!
Part 2: Implementing the Plan
