annual/perennial question

[leifus]

What is the easiest way to determine whether a plant is an annual or a perennial? I'm thinking vegetatively

thanks

[Dorts]

Identify it's species!!!

Seriously. Extremely difficult, especially when you add biennials to the mix. It also depends at what stage the plant is.

Digging a plant up would not work, because the general feature of an annual, a single tap-root, can also be found on many perennials.

The number of shoots emanating from the ground may rule out an annual if there are more than one, but would not define a plant as a perennial as many are single-stemmed, ie. monocots such as orchids.

Is the plant 'woody'? If yes probably perennial.
Does the plant have a large seed-pod with many seeds?
If yes, probably an annual or biennial.

Habitat could help to some extent. Most wild-plants in a cornfield are annual, most plants in a lawn are perrenial, etc..

So maybe, taking these and other factors into acount, it would be possible to whittle it down to within a whisker of being right.
Good question Leif.
Dorts.

[treecreeper]

Once I was out with the Liverpool Botanical Society and one of the members showed me how to diagnose annuals by yanking them out of the ground. She demonstrated on an Italian ryegrass. 'It pulls like an annual', she said, uprooting it with a firm tug.

Not recommended for scarce plants

[Dorts]

Originally Posted by treecreeper

Once I was out with the Liverpool Botanical Society and one of the members showed me how to diagnose annuals by yanking them out of the ground. She demonstrated on an Italian ryegrass. 'It pulls like an annual', she said, uprooting it with a firm tug.
Not recommended for scarce plants

Yes, I agree, there is a general truth to her theory, but I can also think of a number of perennials that could be up-rooted with a good 'yank'.

I suppose the answer to leif's question get a little more difficult if 'yanking' is not allowed.
Dorts.

[King Edward]

In general, an annual (or biennial) is going to channel all of its resources into producing the maximum number of flowers and seeds, while a perennial needs to save its energy for ongoing vegetative growth. Many perennials won't flower at all while they're young, instead devoting all their energy to growing bigger. They'll also commonly have storage organs, often underground, to store up energy and nutrients e.g. plants with bulbs, rhizomes.

Many perennials also have ways of spreading vegetatively, such as creeping stolons (runners), rhizomes, bulbils and non-flowering shoots. And they are often more firmly rooted as well.

[leifus]

thanks for all your replies!

I was going through a grasses key yesterday and came across 'if it's perennial go to..if it's annual go to....' and went ....
I shall just have to combine all those factors I think! Maybe with less of the yanking though..

[Dorts]

I think with the grasses leif, treecreepers botanical lady and her 'yanking' advice may have to be the answer after all!
Dorts.

[bigdave60dog]

Don`t think it can be done. Plants that are annuals in some situations are perrenial in areas with mild winters.
Others such as Evening primrose have annual, biennial and perennial strains within one seedhead. It is thought that this is to counteract years with poor growing conditions.
Growing conditions will drastically alter the appearance of a plant eg. drought will make plant look "woody"
Dave