Garden Phlox So Tall It Droops!

Hi all...last summer, I purchased and planted three clumps of garden phlox ("David", I believe) from Home Depot. I cut them back to ground last fall and they flourished this spring...beautiful and SOOOOO fragrant! My problem is that they have grown so tall and thick that the weight pulled the blooms down so that they're nearly on the ground. The stalks are very thick and sturdy-looking, but they are nearly 4 feet tall and are drooping from ground level. Does anyone know if it's common to have to provide extra support around the base of these plants? Thanks in advance!

Yes, faygoc, it's not unusual to have to stake tall flowering plants, especially the ones that get big, fat flowers. But some garden conditions will also make the need more pronounced. Rich garden soil and fertilizer (especially ones like Miracle Grow) will encourage the plant to grow faster, with weaker stems. Sometimes after dividing a plant, I will end up with more than I have room for and I will plant the extras in an uncultivated area ala "live or die,". It's not unusual that those plants, although shorter overall, are the ones that will stand up on their own and look the best.

Also if you've had rain, that'll often knock tall plants down and they have a hard time getting back up again. And too much water (whether from you or from the rain) can also contribute to the fast weak growth along with the other things that daphnecat mentioned. Those are all things to keep in mind for next year to prevent them from flopping in the first place, but for now since they've already flopped over, really you don't have any choice but to stake them.

Many phloxes have prairie origins, and may therefore have evolved to depend on neighboring plants for partial support. Also, phlox are fairly deep rooted, and may just need a couple years to get their root systems developed enough for good anchorage. I agree with daphnecat that too much nitrogen fertilizer will cause the problems. 4' is a very tall phlox. The native prairie phlox species I'm most familiar with generally are 1-3' tall unless you do something like pour on the nitrogen.

You may have to either stake them or plant more of them (or other plants) so that there isn't space around them and they can support each other. That is how they would grow in the wild, and the keeping space around each plant style of gardening may just not work. They also will likely fill in themselves over time to give themselves the density to become self-supporting by individual stems leaning on each other. Try the staking this year, then see how they do each year. You will likely find that staking is a temporary measure.

Everything said above is just right, where I live, I do have to stake most of my perennial plants because I live in a windy area on the ocean and every year, just as they all look like they were from a mag, the skies open and all the large flowerheads cause the plants to droop over, so I have learned that stakes go into the ground around the plants just as they send up nice soft shoots in spring, then the foliage grows up and out, by flowering time, the stakes are well hidden and the plants are more natural looking, but I also companion plant, that is, I grow things a wee bit closer together, so that they all grow into each other and that way, they offer suport to the neighbouring plants and it all looks softer and blend in better, it helps to supress weeds also, but just check that the base of the Phlox has not been nibbled by any slugs, earwigs or other insects that take bits out of half the stems and this can cause the stems to fall over too, but I really suspect that they are over fed, over wet on the flowers heads when rain or watering, or just grown too tall in this years unpredictable weather everyone seems to be experiencing. Good luck, Weenel.