Generally, training a paniculata into a standard or tree form begins quite early, when the plant is little more than a tall seedling - I have no idea how successful you will be with a plant that already has some maturity and size to it, but it could be worth a try. Or you may want to try some from cuttings of your existing shrubs - this may be a more successful approach. You want to select a stong stem that is growing vertically or nearly so and as straight as possible and remove all the others. Staking is probably a good idea until the branch/leader has developed some girth and structure and becomes self-suporting and that could take time. You want to remove any lateral shoots that may emerge along its length except for any terminal growth. Terminal growth should be allowed to develop unchecked as this will be needed for the photosynthesis required for the plant to convert energy and nutrients into food. Gradually, the lowest terminal growth is removed until the stem has extended to the desired height, forming your trunk. The canopy can then be shaped as desired. This is a process that takes a number of years to achieve. Commercially grown tree-form hydrangeas are at least 5-6 years old, often older depending on size and the training and pruning is pretty consistent throughout this time period. That is one reason why tree hydrangeas typically have some hefty price tags associated with them compared to shrubby ones - you are paying for the additional time it takes to get this plant to a marketable size and for all the considerable hands-on effort of the grower. An alternate method that may be more appropriate for already established plants such as yours would be to select several (3 or other uneven numbers are suggested) of the strongest and most upward growing stems and focus your attention on them. Remove all the other stems at ground level and again, continue to remove all lateral shoots that emerge from the framework stems until you have achieved the height you want. You won't exactly have a tree per se with this method but you will have most likely get a taller shrub with a much more tree-like appearance. Again, I'd suggest staking with this method as well as the flowerheads will weigh down the branches until they reach a diameter and woodiness to be self-supporting.

Thanks for your input whaas, & I agree! I get some yellowing leaves each year during a heat-wave spells but never this concerning because of the amount of yellowing leaves as you may have seen in the pix I posted. Last season we had a longer & uninterrupted heat-wave but preceded by a long spell of uninterrupted rain that got the soil somewhat boggy even. The problem then was steam-cooking others but not the Hs. This year it is scorching ~ for the others (my petiolaris & Macs) as the amount of rain was less. Last Winter's snow was also less & I neglected to water the Divas that required old cane protection ~ resulting to more dead old canes = less blooms (sigh) but all of them are making up by tremendous growth spurts! I'm looking into more challenging over-wintering chores w/ the sizes of these Divas & they are still flexing their growth-muscles! Hopefully these heat lets up soon for all of us ~ today's extended forecast is promising for us!

Hilda, so sweet of you to offer, I'm sending you an email. Ego, thanks for clarifying about the VS and PW. I am very surprised to hear how much growth the VS put on in one season. If the two varieties are so alike, I wonder if they take on similar fall coloring? I have seen the PW and thought the pink color turned a little darker than I was hoping for. I like the rose color the regular PG turns. That is some huge good looking PG! I have a house in our neighborhood that has PGs growing along two sides of their property in a straight line. They are behind a solid fen*ce now although they grow at least 5 ft above the fen*ce. They were visible with a previous post and rail fen*ce for a long time. They soured my desire to have one because they were awful any time of year except when in bloom and they were uncared for and they were bare 3/4 of the way up and had ugly ugly trunks. So it was really eye opening to see that photo of a well cared for PG. [g]

Thank you for the good wishes, Donna! 'Lemon Gold' is putting up a scape here presently. It's been an easy variety for me. Did yours fail to root and/or succumb to rot? The price increase is unbelievable. I have a group of mislabeled bulbs from Komoriya that they haven't been able to ID. Some of them are stunning. I'm glad that you like the "ugly duckling." I apologize for belittling its appearance. I hope that your bulbs will thrive in the whiskey barrel. They are very expensive here, and they don't endure for more than two years in the winter damp. I'm trying my best to narrow my focus to the species, primary hybrids, my own crosses, and cultivars that truly capture my heart. Given the sheer size of my collection, just keeping up with watering and fertilizing is a time consuming task that requires several days each week. Yet, with seedlings, new acquisitions, and the degree of my obsession, numbers continue to increase. Don't forget that my first botanical passion was the Pachycaul and Caudiciform plants that I've been growing since I was very young. I need to clone myself, or grow extra arms and legs! Beyond their gift of beauty, what I love most about plants is how they respond to nurturing. I apologize for anthropomorphizing, but for me, their gratitude is palpable.