Why Isn’t My Clematis Blooming?

The Mystery of the Missing Clematis

Over the years I have heard from dozens of gardeners asking me why is their clematis not blooming?  Well here is another inquiry on the subject I recently received from a gardener named Kevin:

I know you get thousands of cries for help, but I am ready to dig out and burn my Armandii !!!!! When I bought it from the garden centre [sic] it was a mass of flowers, (9 years ago) since then I have had 3 blooms on it! I have moved it, pruned it, fed it, shouted at it and even begged it but it will not flower! Is there anything I can do that might save it and my sanity?
Thanks for reading this, regards Kevin.

I wish I had an easy solution for Kevin’s dilemma but because there are just too many variables to consider (i.e. growing conditions, etc.) and without being able to personally witness the conditions, I just don’t offer an opinion when asked these types of questions.  What I can do though is suggest that you personally involve yourself by becoming a real-life gardening sleuth and putting on your cape, your chapeau and get out your trusty magnifying and start searching for clues that will aid you in solving your own heinous clematis mystery crime.  Below are some of the clues to hunt for that will certainly help you in your detective work in trying to crack your missing flower case. 

Clues to Look For

First Clue: Size of the Root Ball

How big is your clematis’ rootball?  If you have purchased a tiny clematis (which is anything smaller than a quart and includes those miniscule clematis that are being sold in “bags” at big box stores) it can take up to three years for these preemies to ever bloom (that is if they manage to survive the rigors of Mother Nature in the first place).  Being the Clematis Queen, I would like to go on record as saying that I consider selling these incredibly immature clematis plants a real misdeed if not a criminal act to customers.  The fact is the bigger the rootball the better the chance of your clematis growing up to be a well-established plant and providing you with lots of blooms in a reasonably short amount of time.  My advice is to always buy the biggest plant possible.  For more information about the subject of the size of the rootball see: Where Can I Buy Clematis?, Buying Clematis Mail From Mail-Order Nurseries or How Old Are Mail-Order Clematis?

Second Clue: Location, Location, Location

Invariably the location in your garden is probably one of the biggest problem areas for sleuthing.  It is a minefield of potential complications.  I hope I have remembered to address most of them here (if not I will add them at a later point).

What is the soil’s pH?  Does it the range from 6.2 (slightly acidic) to 6.8 (very slightly acidic)?  If not your clematis may not be able to obtain all its needed nutrients (see FYI on Soil pH).

Are you adding “lime” to you planting site?  If so, I suggest you read my article on: To Lime or Not To Lime to see if liming is really a good idea.

What is the lighting like?  Yes, clematis can grow in the shade, but not a dungeon and even then it only uses this limited lighting to create foliage.  As with most plants, the more light (energy) it gets the more flowers it will be able to produce.  Is the location getting 5 to 6 hours of sunlight and/or at least bright shade daily?  If not you may want to move it to a brighter spot in your garden.  So, if you are in doubt grow it in a container for several months and see how it progresses in its new position.

Is the clematis growing in the ground?  What are the neighboring plants like?  Here is an article that tells you which plants to avoid: Bad Neighbors For Clematis.

Is it under attack?  Sometimes a clematis is ambushed by the nefarious root mealy bugs.  What makes these insects so nasty is that they lurk below ground so you cannot see their build up which causes the eventual decline and/or death in the plant.

Third Clue: Feeding Regimen

One of the easiest fixes for clematis that are not producing flowers is to look at the fertilizing program you are providing your plants throughout their growing season.  If your reaction to that statement is: “What feeding regimen?” you could have malnourished clematis on your hands.  Should I say “tsk, tsk”?  Obviously, your clematis are not too happy with you for placing them on a starvation diet and are reflecting that lack of TLC by not providing you with  flowers.  Make sure as well that when you do feed them you are not giving them a meal with too much nitrogen in it?  If so, that is an absolute surefire way to have them produce all foliage and no flowers.  For more information about fertilizing read: Feeding Your Clematis Correctly.

Forth Clue: Cultivars

How are you pruning your clematis cultivars (such as those in the Atragene Group, Montana Group or Armandii Group)?  Are you hacking them down using the hard pruning method instead of the light pruning technique?  If so, you will be removing all of the new growth (wood) which is where the flowers are going to be produced on these cultivars.  Hence, you will not be bestowed with flowers this year (or until it produces sufficient new wood again).

Fifth Clue: A Strong Hybrid

Is it a strong hybrid?  Over the years I have once in and while had the sad misfortune of growing a weak hybrid that has only been able to produce spindly growth.  Unfortunately not all clematis are created equal and in those instances when none of the above clues led me to finding evidence that could help it I had to be brave and cut my losses, i.e. I dumped the little wimp.  I can just imagine the horror on some of your faces after reading that, but I realized if that clematis continued to not bloom what was the point of prolonging the agony for both me and this sickly clematis?

I sincerely hope these clues will help you solve the mystery of your missing blooms and that 2014 will be the year your bloom-doomed clematis comes out of it flowerless slump.  If not, you may want to consider my suggestion above and swap it out for a new, stronger one that has a nice big rootball.