MONTHS - INFO
A flower will get an entry in each and every month in which it flowers. This is a guide only, and does not take into account any global warming that has happened in the last 20 years from 1990, where warmer temperature in extreme months prolongs the growing season of some plants. Nor does it take any account of natural, apparently random, yearly variations.
For instance, in recent years Britain has experienced warmer winters and this has resulted in the early flowering of snowdrops at around Christmas time, whereas they normally flower a month later. The Winter of 2008/2009 bucked the trend, it was colder than of late, and the flowering time of snowdrops fell back to late January 2009.
In warmer winters it is not now (2016) unusual to see plants growing though the winter, and in the south, flowering over winter. The whole flowering seasons are being messed about with by global warming, resulting in the vectors upon which the plants depend (such as for pollination and other both found and unknown synergisms and mutual dependencies between plants and other organisms) being tipped upside down. Species loss is accelerating apace in part as a result of these interdependencies being broken, and in another part by some plants not being able to grow as well under constantly changing conditions. The weather is now unstable on a day to day basis - hot, cold, warm, dry, wet - altering much more often than it has in the past. The wind speeds in bad conditions are also increasing as is their frequency of occurrence. Witness the recent meteorological naming of severe storm systems, the UK now gets through a whole alphabets worth in just a year.
Neither does the data of the flowering months reflect the large differences north and south. In the warmer south of England, flowering could be up to three weeks earlier. Conversely, in the colder north of Scotland, flowering could be delayed by three weeks or more. This is assuming any particular flower grows in both locations; it may not (and similarly for habitats). But there are exceptions: with some plants it is the other way around, that is: some flowers blossom earlier in the north and later in the South.
COLOUR BY SEASON
START OF FLOWERING SEASON
There is a tendency for smaller plants to flower earlier than large ones. This is probably due to the intense competition between plants, all vying for a place, many for the same spot! In order to avoid being put in the shade by large plants, smaller ones may have opted to grow and flower before the large ones even get started.
Throughout the year differing plants come into flower, set seed, and fade, a sort of time-division multiplexing. Many plants have a very specific time in the year when they flower, varying their time spot by much less than three weeks either way in hard or soft winters. It is unclear how they accomplish this extraordinarily accurate timing over such a long 365 day year. Some of the timing must be down to 'timing genes', but not all. They must also be able to glean extra information from elsewhere, if only to 're-synchronise their watches' over millennia (the day length is increasing as is the year length). The average day temperature could be one trigger, and this could account for much of the delay in flowering in cold springs, and earlier flowering in warm ones. Plants might get another clue from the average day length. Day length is rather more stable and invariant than average day temperature; it is highly accurate as a means of determining (given the same position on Earth) the time of year. Cloudy or sunny, day length is an acutely precise means of ascertaining the time in the year (given that you already 'know' certain parameters, such as the maximum day length, and the fact that day length traces a sinusoidal graph - and realising that there is no point in waiting until day length is greater than 24 hours! nor of waiting longer than 365 days...). The plants probably use all means available for determining which time period in the yearly cycle to flower. Exactly how they accomplish this amazing feat is still largely unknown but is being un-ravelled.
LENGTH OF FLOWERING SEASON