Most mint plants can be
invasive, at least to the low maintenance garden, so you will need to examine your
approach to growing them, before you start. Pots and containers are fine, but
mints do not thrive
without a moist soil, in the summer, and good fertility.
Being herbaceous perennials
the top growth dies down during the winter, whilst rhizomes ride out the cold
and wet weather underground. If not too wet, which may result in all the
rhizomes rotting, especially in pots, new shoots appear above ground in the
spring, from the underground leafjoints (or nodes) on the sections of rhizome
that have come through the winter. At
this time good fertility is necessary, which could be a problem in pots with
peat or coir composts that only contain chemical fertilisers. So pot on as soon as the weather
starts to warm up, but if you are going to repot wait until the temperature is
much warmer, or keep in a frame or cloche for a while after repotting.
Pennyroyals and Corsican mint are different.
Flowering usually
starts from July and varies in time, form and colour according to which mint your
grow, and your latitude and altitude.
If the plant is for the
kitchen, use non-flowering shoots. If you start picking regularly before flowering
this probably
means they won't
get a chance to flower, but if
they do then cut the plant down to a few
inches of the ground, water well and give at least one liquid feed, or top
dressing, unless they were repotted into new compost. New shoots
of leaves will grow within a few weeks in summer. In autumn regrowth will be
slower and less compared to summer. If you want mint for the winter you will
need to take lifted and shallowly repotted rhizomes
into a continuously warm, protected and light environment.
(These plants will have to be discarded at some point unless you are going to
give them a lot of TLC to build up their strength again.)
Remember the more leaves removed from a plant, the slower the growth of
the plant, so it may be worth having two or three pots or plots of mint on the go at
all times (depending on your consumption) only picking
from one at a time, while the other(s) have a chance to recover, build up
their strength and provide new
shoots for you.
If you do have a mint
patch in the ground, give it as much room as you can, keep weed-free,
especially of grass, give it at least an annual top-dressing of well-rotted
organic matter, feeding and watering if your soil makes this necessary. It is
likely that you will need to overhaul the patch every 3 years if your
soil is fertile. It would be better to move it to a different spot if
possibly, otherwise dig out and discard the dead rhizomes and replant the live ones after
adding organic matter and some plant food. With the fertile, moist soil mint
needs for good growth, a plant will spread more than you might expect. In late
summer and early autumn rhizomes
will be extending a considerable distance in
all directions beneath soil level at the same time as flowering and seeding
(with fertile forms) and this may not become evident until shoots start to
appear in the spring. Plants grown next to each other will grow into each
other within one season. This can be quite nice with contrasting leaf colours
until one mint begins to dominate, but will make
lifting and replanting difficult (except where they have different types of
rhizomes), and probably will have to be done in late
spring when new growth shows which rhizome is which.
You will often hear of
ingenious ways of restricting mints' sideways invasion. Most do not work if
you need complete success. Even pots sunk in the ground will allow some rhizomes
of some mints out of the drainage holes, and most invade onto surrounding
ground from the top. This may be fine for 2 or 3 plants, not so good for 20
different plants with pots closer than one metre
apart.
For pot culture the
bigger the pot the better, Although do not overpot your new 3½"/9cm
potsize plants in spring. I have heard some opinions that wide shallow
containers are better for mints, but this would need much more attention to
watering each day than a standard shaped container. If at all possible repot
with new compost every year. Compost with organic fertiliser present will be
better at keeping you plant happy all year, and the beginning of next year.
If the problems don't
put you off ... sources