Well, it's true though...
Since they use Plant Growth to slow down enemies trying to reach melee range. XD
My first answer would be, probably...
"In what is that a problem?"
I mean, let's face it: from your initial conjuration turn to the time when only 20% or less of the original "strike force conjuration" is still up and battling, you probably dished as much damage as what would two or three martials properly built would do. It may feel frustrating because you don't do directly damage, but that doesn't change the fact.
Same with a Plant Growth / Sleet Storm: it's even more subtle because it's more of a defensive move, but properly set up it shifts power balance tremendously.
So you should never be ashamed of "just" using Thorns Whip on regular turns.
With that said, I understand the will to bring hurt directly from your hands. So on that ground...
IF MULTICLASS IS ON THE TABLE.
Pick Ranger 5, very simply. Gloomstalker being by far the best pick for such a dual-class, although Beastmaster fits more thematically. You'll get added proficiencies and Extra Attack plus a few interesting spells, extra WIS on Initiative, Rope Trick (-> easy short rest).
OR pick Monk 5, equally simply, with Kensei being by far the best archetype if you stay in classic Shepherd tropes: you get magical longbow attacks, reaction against ranged attacks, decent unarmored, and Dodge/Dash as a bonus action. What's not to like?
Sorcerer and Warlock 3 to 5 should be quoted too: first for Metamagics (Extend being invaluable to make the most of your conjurations when in long runs, plus access to some great defensive spells like Mirror Image, Shield, as well as Careful metamagic to make some Druid spells easier to land), second for short-rest refreshing slots (welcome, "perma" Conjure Animals for travel) and interesting defensive spells (Hexblade for Shield obviously, Armor of Agathys) or features (Great Old One to silently command your beasts without revealing your position).
IF DIP IS ON THE TABLE
Arcane Cleric 1, Grave Cleric 1 or Tempest Cleric 2 (with Booming Blade from whatever way) are nice ways to expand your capabilities: Sacred Flame upgrades your damage (and range!) when you don't need pull, Spare the Dying as Grave makes it easier to keep allies up, Booming Blade for melee or Ray of Frost for distance are always helpful.