IT ALL STARTS HERE
This guide is your first step towards growing beautiful, seasonal flowers. Here you will learn about the basics of plants, their most fundamental needs and how to cater for these needs to ensure an abundance of happy flowers.
Here is a quick list of what you will be learning in this guide:
- Know the characteristics of different plant types in terms of their hardiness, growth habits and seasonal requirements.
- Choose the right plants for your garden
- Understand the basics of how soil impacts plant growth and learn how to test the general quality of your soil.
LET’S DIVE RIGHT IN!
1 | Key plant types
We don’t need to tell you that the world of plants is a vast and diverse one, which is exactly why it can feel so daunting when having to choose what to plant and when and where to plant it. Below you will find a breakdown of the main plant types that you can fill your garden with to ensure that you have flowers and other material for the most part of the year.
Arguably the type that has the most showy varieties, tender annuals are also the easiest (and cheapest) category, providing you with flowers over a long period. Generally sown from early spring onwards, they start flowering at the start of summer and continue until the weather starts to cool around mid autumn at which point the plants go to seed and die off. These heat-loving plants have a relatively long window during which you can sow them as well as a long flowering window. If you are a beginner gardener, this is your category! They are cheap, easy to start from seed and the quickest to flower, all the while requiring little maintenance to put on a great show. Click here to browse our annual varieties on offer.
Cosmos, Amaranthus, Scabiosa, Zinnia, Celosia
This category is somewhat less straight forward than the tender annuals. While these plants share a similar spring sowing period, they have an additional autumn sowing period which provides some flexibility. There is a catch, however, which pertains to the specific plant’s cold hardiness or ability to handle frost. In areas that have particularly cold winters, hardy annuals can be sown in autumn whereas less hardy (or semi-hardy) annuals should only be sown in spring. In areas that see milder winters, both hardy and less hardy annuals can be sown in autumn as well as spring. It all comes down to the hardiness of the plant and the corresponding hardiness zone (see Did you know below for additional context) of the area that you are in.
Since our main goal is to grow the best possible quality flowers, it has to be noted that autumn sown hardy annuals provide better quality stems and higher productivity than spring sown hardy annuals. This is because autumn sown plants will have had much more time to grow a strong root system and larger plant during the colder months, which results in more and better quality flowering stems during the warmer months. Just to reiterate, this is only applicable to an autumn sowing of hardy annuals in cold areas and less hardy annuals in milder areas. If you can manage an autumn sowing according to these guidelines, your hardy annuals will reward you with flowers long before the tender annuals start flowering, handing over the baton to them when the weather starts getting hotter.
Cornflower, Snapdragon, Larkspur, Queen Anne’s lace, Nigella
Are you with us so far? Good, because there is just one more snag to highlight… Some hardy annuals actually require a period of cold weather to properly initiate flowering in spring, which means that they have to be sown in autumn, even if they are being sown in a milder climate. In other words, even if you live in a milder climate, some hardy annuals have to be sown in autumn (to initiate proper flowering), while other hardy annuals you will be able to sow both in autumn and in spring. But not to worry, we have indicated the climate and sowing details for each of our flowers so that you will know exactly when to sow your favourite varieties. Refer to the map below to see what climate zone your area falls in.
DID YOU KNOW?
Hardiness zones are geographical zones where specific plants grow the best in those specific climates. The US and Canada is divided into 13 zones (Zone 1 most northern and 13 most southern), while each zone is split into two, i.e. Zone 1a and 1b. Plants that have a hardiness zone indication of 7b (5-10C) will not thrive in Zone 7a (0-5C), nor any zone less than 7a. Conversely, cold hardy plants will not tolerate very hot climates. Heat climate zones are also defined, but we will not be delving into that.
The different climate zones of South Africa do not correspond to the US hardiness zones mentioned above, but they do exist of course. The map shown on the right indicates the different climate zones for South Africa.
In reference to the above map, we reside in Zone 2 (Mediterranean climate) which correlates with a winter rainfall pattern (350-1000 mm per annum), usually between late autumn and early spring. Summers are hot and dry with periodic droughts with an average daytime temperature below 30oC. As with most of South Africa, frost occurs more towards the inland than on the coast. This region has a similar climate to the northern Mediterranean and southern California. If you would like to read more about the other Zones in South Africa, visit https://whiskerflowers.wordpress.com/2017/12/20/south-africa-climate-hardiness-zones/.
In other words, if you live in climate Zone 2 (Mediterranean climate), your area experiences a mild winter, which means that you will be able to sow some tender annual varieties in autumn already. If you live in Zone 1 (Hot arid), you might experience heavy frost in winter, which means that you will only be able to sow tender annual varieties in spring, but you can sow hardy annual varieties (capable of surviving heavy frost) in Zone 1 in autumn already and they will survive the winter frost.
Biennial / Bi-annual – is there a difference?
Some of you might have come across the terms biennial or bi-annual referring to flowering plants and this is something that is potentially a bit confusing when you are busy considering which plants to grow. To put things into context – biennial refers to something occuring every two years or lasts for two years, whereas bi-annual refers to something that occurs twice a year.
Therefore, a biennial plant is a plant that takes two years to complete its cycle, from seed to seed. In its first year, the plant focuses on vegetative growth (roots, stems and leaves) before it goes into dormancy over the winter months. Many biennials require this cold weather (see Pro Tip below) before ramping up their growth again when the weather starts to warm, after which it focuses on reproductive growth (flowering and setting seed) during the summer months in the second year. Following setting seed, the plant then dies back, thereby completing the biennial or two year cycle. The term bi-annual is not commonly used with plants, but it might be used to refer to plants that flower twice within a 12 month period, e.g. flowering in spring and then again in autumn.
Foxglove, Sweet Williams, Delphinium
It is possible to “trick” some biennials into thinking that they have already undergone a cold period. This is referred to as vernalisation and entails cold storage of the seed for a period of time before attempting germination, this time at warmer temperature. Using this cold treatment, we can reduce biennials’ time from seed to flower down to a couple of months, ensuring that they flower in their first year already. Interestingly, some newer biennial varieties have been bred to be so-called first-year-flowering (FYF) plants.
Our last plant category is perennials. These plants live more than two years and consist of smaller flowering plants as well as shrubs and trees. Perennial flowering plants generally grow and flower over the warmer (spring and summer) months after which they die back during the colder months, only to reemerge (from their existing roots) the following spring. Many gardeners and growers choose to ignore the “perennial” status of these plants, treating them as annuals. To explain, if a plant finds itself growing in a climate that is much different from the climatic conditions of its native habitat, it might not survive a colder winter (or a hotter summer for that matter) than what it is used to growing in. In essence, the plant then dies and effectively has the growing habit of an annual.
You might see that some seed packets indicate conditions required for the plant to grow as a perennial, for instance: “Perennial in Zones 8-10 (US Zones)”, which means that if that specific plant is grown anywhere outside of hardiness Zones 8, 9 or 10, it will most likely not perform as a perennial. These plants are also known as “tender perennials”, meaning that they are tender and do not survive extreme cold weather. They would therefore perform as perennials in milder / warmer climates.
Yarrow, Dusty miller, Eucalyptus (tender perennial)
You will undoubtedly be aware of the existence of these lovely and interesting plants. They come in all shapes and sizes. Whether tubers, bulbs or corms, what they all have in common is that these structures are primarily a food storage source for the plant during a period of dormancy.
While a vast number of indiginous bulbous plants exist, there are also many varieties in the same family (cousins if you will) that have been cultivated specifically for their impressive flowers. We will only be mentioning a few of our favourite varieties here. As with the previous plant categories, these plants have their own optimal sowing and flowering seasons.
Spring Flowering Bulbs
These bulbs are generally planted in autumn so that they have enough time to develop roots and vegetative growth (leaves) before the colder winter months. The cold period is essential to trigger proper flowering in the subsequent months. As soon as the weather warms, the plant sends up multiple flower spikes for the whole of spring and early summer. They are usually very early to flower and therefore ideal to bridge the gap between winter and spring, flowering before the hardy annuals. These plants usually do not fare well with high heat, so as soon as the temperature climbs, flowering slows down and the plant directs all its resources into the storage organs (the bulb), after which the leaves die back and the bulb goes into a period of dormancy.
Ranunculus, Anemone, Daffodil, Tulip
Summer Flowering Bulbs
These bulbs are generally planted in early spring and immediately start to develop roots and vegetative growth. They thrive on high heat and as soon as the temperature climbs, the plant sends up multiple flower spikes, lasting the whole of summer and most of autumn. When weather starts to cool down, flowering slows down and the plant directs all its resources into the storage organs (the bulb), after which the leaves die back and the bulb goes into a period of dormancy.
Dahlia, Gladiolus, Freesia
In general, bulbous plants can be seen as tender perennials as they do not survive extreme cold / frost. If these storage organs receive frost for extended periods, they rot and die; but if grown in a milder climate, they will exit their dormancy period as soon as they experience temperatures that are optimal for vegetative growth and the cycle starts anew.
Plant Type Summary
The table below provides a general summary of when specific plant types should be sown and when you can expect them to flower. Note that the length of the sowing period indicates that you would be able to sow plants at any time during that period. Flower growers use these windows to their advantage, staggering seed sowing over the whole period, referred to as succession planting, to optimise flower production over the whole flowering period. More on succession planting in the next guide.
GOAL 1 | KEY TAKEAWAYS
* Different plant categories have differing seasonal growing requirements
* Hardiness zones are geographical zones indicating where plants grow best in those specific climates
* A plant’s hardiness or ability to handle cold weather, along with the location’s hardiness zone, determines in what season they can be grown in that specific location
* Sowing or planting according to seasonal requirements is crucial to the plant’s success
* The number of plants in the biennial category is a lot smaller than in the annual and perennial categories.
*Growing a number of plants from each category is ideal to ensure you will have flowers and other material for most of the year.
Now that you have a grasp on the different types of plants and when to grow them, let’s have a look at some options in each of these categories for you to grow and where to put them! Next up is Choose the Right Plants.